Como reparar o Ubuntu depois de bagunçar as permissões em diretórios críticos?

Então eu executei um comando estúpido como root ( NÃO EXECUTAR ISTO )

# chown -R root:root /{usr,lib,var,etc,bin,sbin,tools}

Então... opa. Acontece que eu tinha um shell de root aberto (de quando causei isso), então consegui sudotrabalhar fazendo

# chown root:root /usr/bin/sudo
# chmod 4755 /usr/bin/sudo

Eba, sudovoltou a funcionar. Eu queria instalar um pacote ( ncdu), então executei sudo apt-get install ncdu.

$ sudo apt-get install ncdu
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
  ncdu
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/43.4 kB of archives.
After this operation, 106 kB of additional disk space will be used.
Selecting previously unselected package ncdu.
(Reading database ... 233654 files and directories currently installed.)
Preparing to unpack .../ncdu_1.15.1-1_amd64.deb ...
Unpacking ncdu (1.15.1-1) ...
Setting up ncdu (1.15.1-1) ...
Processing triggers for man-db (2.9.4-2) ...
/usr/bin/mandb: can't chmod /var/cache/man/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/es/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/es/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/es/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/zh_TW/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/zh_TW/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/zh_TW/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/fi/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/fi/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/fi/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/de/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/de/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/de/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/uk/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/uk/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/uk/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/sr/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/sr/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/sr/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/sl/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/sl/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/sl/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/nb/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/nb/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/nb/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/pt/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/pt/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/pt/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ru/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ru/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ru/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ko/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ko/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ko/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/it/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/it/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/it/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/fr/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/fr/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/fr/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/et/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/et/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/et/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ca/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ca/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ca/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/tr/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/tr/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/tr/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/nl/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/nl/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/nl/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/fr.UTF-8/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/fr.UTF-8/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/fr.UTF-8/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/hu/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/hu/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/hu/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/fr.ISO8859-1/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/fr.ISO8859-1/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/fr.ISO8859-1/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/sv/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/sv/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/sv/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/id/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/id/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/id/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/el/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/el/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/el/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/pt_BR/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/pt_BR/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/pt_BR/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ro/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ro/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ro/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/zh_CN/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/zh_CN/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/zh_CN/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/cs/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/cs/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/cs/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/gl/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/gl/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/gl/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/da/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/da/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/da/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/pl/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/pl/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/pl/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ja/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ja/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ja/1053532: Permission denied

Claramente eu não fiz o suficiente para consertar meu sistema. Prefiro não reinstalar o sistema operacional, se possível, mas tenho um shell de root (é um laptop físico na minha frente), então estou querendo saber como consertar aptpara poder instalar os pacotes novamente. Estou usando o Kubuntu 21.10.