[rvnx]

In such case: sudo su, then.

and let sudo verify that the user belongs to the group of allowed sudoers.

No need for the password to the root account.

[rollcat]

Objection: su is a very simple program that does (approximately) one thing. Meanwhile the sudoers(5) man page starts with an introduction to EBNF grammars.

I strongly prefer doas wherever it's available.