Yep, happened to me too. I thought it was some kind of a browser issue. I guess I was wrong...

Well, since you love KeePassDX as me, I started to use KeePassDX as a "database of notes". Under Root, you can create categories by adding 'Group's. Inside each group, you can add an 'Entry' (a note). each Note, will have a sub Category (Title), subject of note (User name), url and the note itself (note). you can also add tags to your notes.
Give it a go, you'll be surprised how well this works, finding/searching for whatever is there.

You could install Droid-ify, it has a setting that lets it automatically install F-Droid apps

What about Collabora Office?

Same here

Should this work on an Android device (I am using a brave browser), or just on desktop?

It gives me a GPT3.5turbo and GPT4 options. Not sure what's "turbo".

I am just a regular 3.5 user

I've added an API Key and still getting: An error occurred while fetching a response.

Another vote for Bitwarden

Great list, here are some more apps to consider to add to the list: InnerTune, Amaze, DiskUsage, DuckDuckGo, K-9 Mail, KDE Connect, Video Transcoder, Notally.