PostgreSQL's approach isn't the most intuitive but it's well documented and very powerful. A few aliases could probably help, it's good they've added `quit`/,`exit` this time around.
postgresql still seems to have 2 ways, but the majority of tutorials will demonstrate the "become the postgres user and add unix-level accounts". Things like having a unix-level "adduser" program that manages pg stuff is... odd to me, because it's not 'self-contained' in the app. It's more system-level admin stuff I need to do or be aware of.
Whenever I bring this up, I get push back that I'm doing it wrong, and that of course you can just create user accounts from within pg itself via psql, and ... all other sort of attendant feedback. This approach had not seemed to be the norm/default approach, nor the one that was in multiple postgres books I had 10 years ago.
I use pg on some projects, but am no expert in it.