I recently bought a second hand Pixel 6 and installed GrapheneOS on it.
Couldn't be happier. Surprisingly it's one of the most straightforward ROMs I've used, and I've used many over the years.
Glad to hear it! Mine still hasn't arrived yet but I'm very eager to give GrapheneOS a try. Tried LineageOS a few times over the years but when paired with microG it's barely usable, and with Play services I might as well just stick with stock.