Dumdum
By "Tick Fdroid Options" I was referring to the screen you get after first installing Obtainium, it has tick boxes where you want it to grab apk's from. I only ticked github as I thought ticking Fdroid will leave me open to the same security flaws of installing via Droidify (as I used to do).
From what you said above it sounds like I was indeed wrong, and that's not the case.
So just to confirm, are you saying that if I let Obtainium install apk's from fdroid repo, that's different than installing that same app from Froid via the Fdroid or Droidify apps?