That is way too much work. Doing work means stuff is happening and stuff means sidechannel attacks that someone else hasn't audited, because it's not an integrated product anyone would bother auditing.
In particular, I don't see how 2FA is possible with this, so shoulder surfing is a bigger issue.
I definitely trust Google or BitWarden more than a password I can memorize plus my own constant vigilance.
Ah, I stand corrected, I forgot about trusted hardware based 2FA.
Still, it doesn't allow SMS or email based 2FA as far as I can tell, since that involves a trusted server and doesn't mean anything in a trustless model where the server owner could just add a bypass.
In particular, I don't see how 2FA is possible with this, so shoulder surfing is a bigger issue.
I definitely trust Google or BitWarden more than a password I can memorize plus my own constant vigilance.