I've been using Graphene for a few weeks now. I'm really happy with it. That said, I'm a pretty minimal smartphone user. I don't use NFC or any AI or Assistant features.
My only hiccup was my banking app didn't work at first. Luckily their documentation is informative and easy to read. This is a common problem with a simple solution... You just need to change a toggle in the app control setting.
Installation is super easy if you use their web installer - just read through the procedure first, follow it exactly, and be patient. There are a few places where you think it's done, but if you interrupt it, the install can go sideways.
It's also easy to revert back to stock if you want to. And it doesn't void your warranty - I just RMAd my pixel 8 after it developed the pink stripe syndrome.