Yeah, reiterating on others - its an incremental process, try the approach of learning what you need for the immediate task. Graphene let's you use the standard play store, just sandboxed.

When youre more comfortable and have time, maybe self host with Nextcloud.

Im pretty happy with Nextcloud for my scheduling and hosting files, but renting a vps at $12/Month is kind of annoying because the CPU I'm renting is lacking. At some point maybe I'll start self hosting nextcloud for better performance.