I just tried GrapheneOS yesterday. Installation on my new phone was a breeze, but once I was in, there was... Nothing. The "Apps" app, which I assumed was an alternative to the Google Play store, had literally nothing except a link to install Google Play services.
So I installed that and the Play store, which, due to GrapheneOS's sandboxing, was probably better than the stock Android. But it didn't even work well. Plenty of apps I tried to install wouldn't. After about 3hrs of playing with it, I said "fuck it," and flashed the stock Android back onto the phone.
I really want to switch, but that was far too much work.