I have not any prior experience with installing custom ROMs, but after trying it out (and getting stuck, and googling and finding answers) I successfully did it. Below is my home screen if anybody is curious:
I use OpenBoard for my keyboard. Unfortunately I am still dependent on Play Store since some of the apps I need can only be found there. Sometimes it feels meaningless committing to this whole thing because I'm not perfectly private; then I think this is better than using a regular iPhone or Android phone.
So far I'm liking it. I am naturally inclined to feel hesitant about using this as my main phone and plugging in a SIM since it's custom, but I'm slowly making the transition.
Feel free to share any beginners advice or your own experience using GOS for the first time. Cheers!
I've used four different banking apps (admittedly banks which may not operate in your country, but they're popular enough in my country) on GrapheneOS no problems. I currently don't have a banking app installed because I don't need one and it's probably spyware. I just do my digital banking in my web browser. But if you want to install a banking app, it should work completely fine, save for notifications—a lot of proprietary apps seem to rely on Play services for notifications 🤷♀️