[compootr]

What's sufficient depends on your threat model.

Normal dude in a secure office? An auto-locking password manager would suffice.

Someone that should be concerned with passwords in-memory is someone who believes another has full physical access to their computer (and can, say, freeze RAM in nitrogen to extract passwords

My largest concern would be an adversary snatching my phone while my password manager was actively opened

[necovek]

Locking a password manager and your computer is certainly good enough in many cases. But gaining access to memory might not need the sophistication of using nitrogen (see eg https://en.m.wikipedia.org/wiki/DMA_attack).