What does your training routine look like?
Can't go wrong with going back to basics - squat, deadlift, chins, barbell rows, curls, shoulder press, barbell curl and skullcrushers.

Rinse and repeat 3 times a week with a cardio core day and 3 off days to grow or separate upper body/lower body with a cardio core day and only 2 days off and lots of sleep, rest and keep eating. Point is hitting the muscle groups more than once a week every week. You don't need 6 exercises and a week of rest just for pecs.

I've plateaued for years before as well you can fall into the same routines your body cut gets too used to. Switching from the arms / chest / back ect bro split and focusing on loading compound movement barbells with 5 to 10 pounds more every single week hitting 1 or 2 Rep maxes and then pyramid down blew me up.. With a little gear added in.