Tentando fazer uma atualização do Software Updater. Obtenha este erro que parece dizer que precisa do mesmo software que está tentando instalar:
As dependências do pacote não podem ser resolvidas
This error could be caused by required additional software packages which are
missing or not installable.
Furthermore there could be a conflict between software packages which are not
allowed to be installed at the same time.
Transaction failed: Package dependencies cannot be resolved
The following packages have unmet dependencies:
gnome-software-plugin-snap:
Depends: gnome-software (= 3.36.1-0ubuntu0.20.04.0)
but 3.36.1-0ubuntu0.20.04.0 is to be installed
ubuntu-software: Depends: gnome-software (>= 3.36.1-0ubuntu0.20.04.0)
but 3.36.1-0ubuntu0.20.04.0 is to be installed
A partir dos comentários acima, pode-se facilmente deduzir que fazer
sudo apt-get install gnome-software
ousudo apt-get install gnome-software=<version you chose>
resolveria esse problema, pois instalaria o pacote ausente que está causando a falha do Atualizador de Software.