Lightroom Classic uses a lot of resources when actively running, not so much when just sitting their, open. But more when accomplishing Develop Module Edits. Not so much for simple Library Module edits (typically metadata edits by user). A heck of a more use of resources than Photoshop.
Lightroom's use of the GPU when not selecting use Graphics Processor is a bit muddied (other members will step in I assume). When you turn that option on, then the use of the GPU might increase in certain instances.
Now another suspect to include is any sync that is going on, what sort of sync, what sort of edits occur in the sync, Face detection could be very resource nasty. Address Lookup less. Sync to the Cloud? more of an internet bandwidth issue, lots of other syncs.
Plating a nice intensive game with lots of cerri0use GPU use? Heck Lightroom's use of GPU is a little child in comparison with some if those. Mind you big games use parts of the GPU that Lightroom has no idea of.
Does your problem mostly crop up during game usage?
Just another Adobe customer; My Sys; APP: LRC 9.4, PS 21.2.1; CMP: WIN WS 16GB OS 10 v1909 (18363), mid 2015 MBPr 15” 16GB MACOS 10.15.6; 4K EXT DSPY; CAM: Canon 5D Mk III, Fuji X-T3