I've been running GrapheneOS for several years now and I love it, and currently run it on a Pixel 9 Pro XL. Super easy to install and use. With respect to the things you can't compromise on, you should be fine if you run the sandboxed Google Play services. I will say that my banking app updated a while back and now will not work with GrapheneOS, saying something about a lack of security, which I assume is because they probably added checks for stock android, so YMMV. If you buy a used Pixel, make sure you get one with an unlockable bootloader. Carrier phones have locked bootloaders, along with carrier locking, and when they unlock them they just unlock the carrier aspect so that you can use them on other carriers, and the bootloaders remain locked so you can't wipe the OS and install another, so you have to make sure you get one with an unlockable bootloader. Some ebay sellers advertise this, making it easy to find what you need. If you ever want to revert to stock android, it is an easy change. Google's "unverified app" decision does not affect GrapheneOS' ability to sideload apps, as it is a completely different OS.