Hey everyone! It's been years since I last posted on here....

I have been having a weird issue with the AC in my 2014 GMC Sierra. The truck has been amazing - however, about 2 years ago I had the A/C condenser replaced as it was not blowing cold. The past few months I have noticed my blower motor has been "surging". The best way I can describe it is if you put the blower on the highest setting, it sounds like it will drop slightly for a couple of seconds, then go back to normal. It will do this periodically for a couple of days and then stop. I will say the amount of air output is nowhere near what it was when I first got the truck. It honestly has not been the same since they replaced the condenser.
I guess my question is should I go ahead and buy a brand new GM blower motor? (I've read the aftermarkets don't work) OR should I buy both a blower motor and Resistor? Or maybe something else?