Regex: encontre e exclua a tag html que está contida em outra tag

Tenho 2 parágrafos, com tag html <p class="mb-40px"></p>Dentro desta tag tem texto e outra tag <p..>

Eu preciso encontrar e excluir a tag html que está contida na tag principal<p class="mb-40px"></p>

Exemplo:

<p class="mb-40px">Miracles every day <p lang="ro-RO" align="JUSTIFY">being at la home, the poet Petru Iliesu made an international appeal to condemn the killing of demonstrators, shot on the streets of town.</p>

<p class="mb-40px">The pleasure we feel after reading a book is different from the pleasure of tasting a dish <p class="dis23">. In the first case, pleasure is disinterested, having no particular purpose, as a release from external preoccupations.</p>

Resultado

<p class="mb-40px">Miracles every day being at la home, the poet Petru Iliesu made an international appeal to condemn the killing of demonstrators, shot on the streets of town.</p>

<p class="mb-40px">The pleasure we feel after reading a book is different from the pleasure of tasting a dish. In the first case, pleasure is disinterested, having no particular purpose, as a release from external preoccupations.</p>

Meu regex não é muito bom:

ACHAR: (?:<p class="mb-40px">|\G)\S*\K(?:\h+<\s*(\w+)[^/>]*>)(?=.*</p>)

Substitua por: (deixe em branco)