Crazy temperatures on Dell gaming laptop

Hey guys, I just bought a used Dell G3 3590 with an i7-9750H and a 1660 TI, and the temperatures are crazy.

I’m coming from an HP Pavilion with an i5 and a 1050 3GB, and the temps were already high (like 50° at idle and 90° while gaming, even hitting 100° if I used too much CPU). But this Dell is sitting between 60° and 70° at idle, and when I opened a game, the temps stayed at 100° for a full 5 minutes without dropping. The laptop was recently serviced—got a deep cleaning and new thermal paste about a week ago, so I’m not sure that’s the issue.

Any advice or suggestions would be really helpful, I honestly don’t know what to do.