I have not tried KeePassXC yet (I'm under Windows), but I wonder how it compares for this kind of setup.
It could be better with good browser plugins, but then you have the same security tradeoffs as more polished services like Bitwarden or LastPass.
This latest version KeePassXC has a whole new browser plugin:
https://github.com/keepassxreboot/keepassxc-browser
So maybe it has reached that point now? Not that I've tried it, but it's at least promising that they've been working on it.
Not exactly. The database is handled with an independent program. With the new model, AFAIK, the browser extensions have no idea what records exist and can only query - and record matching is actually authenticated before plugin sees anything.
My wife, parents and in-laws all use it. The only thing that is a gotcha is sync. It's isn't obvious to folks that when you open a synced vault on an iOS device that it may not sync back.