I had to use MS Authenticator for work and it worked in GOS, notifications and all. Now, that was about a year ago, and I haven’t tried it since. At the speed GAFAM are enshitifying everything, there’s a chance it doesn’t work anymore. I keep a Pixel 8a stock for banking and some other apps that I need (such as EV charging networks) and won’t work or are unsustainably wonky on GOS. As I mentioned in another post, RethinkDNS is worth it, but it does take some trial and error to get it to work without breaking stuff I need, but once I got there, it was all good (that’s how I keep the 8a less intrusive).