"AI overview" (which I happen to find really useful) was only available on Chrome and Safari for at least a few months.

Sure, it's a lab experiment or whatever, but these are just words, and the effect is that I have to use a different browser to be able to use them, for absolutely no technical reason. (The LLM is running on Google's servers and provides plaintext. I think Firefox could handle that.)

Just visit this on Firefox if you want to see for yourself, including a big "install Chrome" call to action: https://labs.google.com/search/install

Doesn't really support your statement then.

Meet is as shitty on Safari as Google feels they can get away with

I don't know of anything that is completely broken, but some functionality requiers chrome:

On Google Docs, paste as markdown, copy and paste from menus, paste without formatting, etc. only works on chrome. This functionality could be done with standard APIs, but instead google uses a hidden, pre-installed extension to implement it.

Offline mode doesn't work on firefox for either gmail or google docs.

Google doodles don't show up on Firefox Mobile, unless you spoof a chrome user agent.

Youtube has repeatedly had serious performance problems on Firefox.

There are less options for screen sharing on Google Meet.