Need help picking a PC

My current PC is Ryzen 7900 12 core 2x 16gb 1600 ram RTX 3070

I want to upgrade or buy a new PC and sell this one. What I am looking for is a PC that can handle a few applications without lagging. OBS, Firefox, voicemeter and a fullscreen game with runelite running osrs on the side. I have 3 monitors. And if I have all this running my YouTube videos will lag and be stuttery. Would I just need to upgrade my ram? Task manager shows cpu usage at 30%, GPU at 100% and memory is at 70%. So is it really a GPU bottle neck? Would I be better off upgrading 1 or 2 pieces. Or just buying a 9800X3D and a 5800 with 32GB DRR5 6000?