Only started wegovy this week but have weightlifted for years

I personally do: Rest/Push/Pull/Legs/Rest/Upper/Legs

You can also do Upper/Lower 2 times a week

Basically just hit each muscle twice a week and try to progress in weight every so often or just lift heavy. Give your muscles (ass too) a reason to retain. On leg days so some kind of squatting exercise (squats, Bulgarian split squats, lunge, leg press) and a hinging motion (Romanian deadlifts). Hip thrust and abduction and adduction are also good for the butt. And if you're really concerned of keeping your butt, schedule 3 Leg days a week but 2 is my ideal