Asklemmy

What about using OneKey so that she mostly needs to worry about remembering a PIN? It looks like you can set it up to automatically open your password manager. Might also need to synch her browsers.

As an added bonus, she would have to hold on to the key without losing it, because if she lost it, she's effectively locked out of accounts forever.

Chrome Password Manager is easily the most intuitive I've found. Tons of people use it without even realising it exists. Auto synced via Google account on android and you don't have to worry about it. Idk if she uses iOS what would be comparable.

Maybe setup a mozilla account and setup firefox on her phone, i'm pretty sure it would sync.

I set up LastPass for my parents but they refuse to use it. My mom got locked out of her Facebook account and can't regain access because she doesn't know the password, doesn't know the email it was registered with, and her phone died so she can't prove any prior access. Too bad so sad. Still won't use LastPass.

I use vaultwarden, and I stumbled upon the generated password history. It's awesome.

Maybe try a different password manager and see if its interface is easier for her to use? There are lots of options, not all of them FOSS but this might be a time to accept a well-regarded commercial solution. Or, since she has the iPhone, try using their password solution. They integrate that pretty thoroughly in their apps and OS, and I think with this year’s OS releases across the board they have turned it into more of a fully-fledged password manager with its own apps. I know very little about it, but there might be a way to integrate it with Firefox on desktop now.