missing-root getting a list of recommended apps
Many lists of recommended apps can be found online (especially in open source spaces), such as DivestOS's.
getting apps from external f-droid repos (needs repo URL and app ID)
AKA, the apps I was referring to when I said:
Dumdum Even the few apps that needed more work weren't that difficult or time consuming.
At the end of the day, as you said, Obtainium has their list that people can use.