5 months out from shoulder surgery of any type is a short time. If your at 80% range of motion and strength, count your blessings. My recovery from shoulder surgery took 15-16 months and mine was not replaced, it was repaired.
Keep at the PT and strength training and you’ll hit full recovery soon enough. G-d Speed for a full recovery.
__________________
“Two things are infinite: the universe and human stupidity; and I'm not sure about the former."
― Albert Einstein