So if a developer where to pull the GitHub code into Xcode and try to install it on their phone to “test”, there would still be certificate issues?
You can distribute macOS apps without going through the App Store.
https://developer.apple.com/macos/distribution/
For iOS, not sure, maybe it’s possible, but not realistic. Even all the Damus developers who is not Will has to jump through hurdles to get the app built onto their iPhones because of certificate issues. Most of us just work through the simulator.
Discussion
I did it once, had to tweak a bunch of settings to get it to work. IIRC i was also only able to do it because i have an apple developer account
Yes — although it does work if you muck around with some configurations but it’s not straightforward and requires turning off some features like notifications.