I am also guilty of tearing my hair out and tearing down allegedly creaky press fit BB86 BBs multiple times. Then I put a Campagnolo Record skewer in. The creaks vanished immediately. Now I use Campagnolo internal cam skewers exclusively across the board and such creaks are a thing of the past.
The test I suggested is dirt cheap and 100% reversible. Can't hurt to try. If it doesn't cure the creak, at least you have a decent skewer to keep in the toolkit for future use/testing.
had the same experience. was pretty sure that the creak was coming from the press-fit bb, turns out that the cause of the creak was my Carbon-Ti skewers. replaced the skewers with campy and the creak was gone....