Just android auto which isnt a big deal for me anymore. Adding an esim was weird but the forum helped a lot. Haven’t tried every app though so I cant be 100% sure but flashing and reflashing back to stock (if you dont end up liking grapheneos) is pretty straight forward and fast. Just backup everything important off of your phone and use a good cable
If ice cream: Vanilla, Its goes with everything like syrups, fruit and even some sodas