I’m in the process of switching from an iPhone to Graphene on a pixel 10 Pro.
I can load apps from the web (disabled by default iirc), the local file system, a sandboxed instance of the Play store, Obtainium, f-droid, wherever.
Took some getting used to, but it’s nice feeling like I actually control and can choose how my phone works.
I've done some research and am considering as well, though I might wait for the motorola phones to release. Have you encountered apps that didn't work? Like banking and stuff seems to break a lot of the time.