I guess the issues you bump into are universal struggles that any new would-be fedi dev encounters. Unfortunately the onboarding to the fediverse is still too hard, and we should continue to improve it to have more people attracted to fedi and create / integrate more different apps.
I don’t know if you’ve seen the Guide for new ActivityPub implementers?
This long document with a ton of links is also a Wiki post that anyone can edit and update with stuff that is missing in the guidelines. If you find that important stuff is missing it would be great to update in this wiki. Hopefully at a certain time we can lift it from its current location and elaborate it into a comprehensive handbook of sorts, and crowdsource further from there to keep it up-to-date.