I'm thinking your mount has been remounted upside down. (Mount should be 2 bolts up, 1 bolt dwn for the spare). I carry a 35" tire on my stock tire carrier. I also keep it tight against the tailgate so I had to space out the bumps on the tg. I do have an aftermarket bumper and have a 1.25" body lift. So that probably helps clear the bumper.
Couple things you can do. 1 - cut off the stock lugs, weld on flat plate on the face, and weld on 1/2-13 bolts Gr5 or 8 bolts. Make sure the plate is big enough to mount your wheel high enough to clear your bumper.
2 - aftermarket has a tire carrier spacer with raises the spare higher, but it also pushes it out farther away from the tg. Not a real good option.
You don't want the spare to vibrate. So you want to keep it against the tg.