Gos is good. It is a solid os. I like it a lot. I have a lot of freedom that I don't have on other phones. But it is also just android. other brands like samsung added a lot of goodies to their os. It is a phone, it works, it's alright. It took me a while to understand that graphene's exploit protection slows down apps. I disable that for all important apps like osmand where speed is crucial. Osmand is still slower than on an iphone 6. Do I have to use it security wise? No, but I like supporting it. Will my next phone have gos as well? Yes. It has no annoyance on it. There is no unwanted app or anything. That's amazing.

Can just confirm the other comment

GrapheneOS is serving me very well
No problems (currently) with banking apps either

I'm very happy with it - although a real Linux phone would be really cool