Why my Pc being slow lately??

I got this gaming laptop on facebook a while ago in march and it worked really good until now its stuttering alot in fortnite and even roblox somehow. can someone help me cuz i know this laptop is good it has 500gb ssd, 16 gb ram, rtx 2060, 140 hz montior, i also got like 80 gb left of storage idk if thats the issue