I can't speak for calyx, but graphene has been great. Most android apps run by default using a stand-in for google play services; some don't, but its rare, navy federal works for instance, but USAA doesn't, you'll have an easy time with mostly anything that isn't related to the government or banking though. For apps that don't work out of the box, you can run them in a sandbox that protects the rest of your data. Its loaded with a lot of nice features, like the camera app doesn't retain metadata, so if I post a picture here I don't have to worry about it tracking me. Its been very stable overall, the only exceptions being user error in not updating the fdroid store apps. I can't speak to battery life because my (and my spouses) phones are both pretty old, but my battery usually holds if I'm not on amethyst all day. It retains all the major UI elements of android, so I'd be confident recommending it to people, I'm trying to put my mom on it soon and I doubt she will be able to tell the difference. Lastly, gives me a great excuse to not install apps to my phone, anytime someone bugs me to install tiktok I miss notifications from work (I turned them off) I just tell em I have a nutter crypto phone that won't let that stuff work.