Poor Performance on Laptop

I have a laptop with an RTX 4090 and an Intel Core Ultra185H. I play with my laptop plugged in. Whenever I load into the menu, I can easily get to 100-150 fps without much issue, even though it does drop at times. Whenever I load into a game, it drops to around 60fps, even though beforehand, when it was loading up the game while showing the contracts, it was holding around 80-90fps. It holds pretty stable around 55fps when the match starts, but whenever I enter combat, it quickly drops to 30-40 fps. Hopefully, this helps.