The first folly is likely setting CPU/GPU usage ratio goals to begin with...
All kinds of folks out there chasing misconceptions of ''too much CPU usage' or, not enough, or " I think my GPU usage should be higher", etc...
Many games will indeed allow fairly high CPU usage , or GPU usage; heck, many might have both...
But one certainly can't just look at a GPU usage and say 'this is not high enough' without knowing the GPU and what resolution the game is being played at? The fastest GPUs with the most VRAM might have moderate GPU usage at only 1080P, where usage will go up with faster CPUs at high refresh rates, or, with faster CPUs trying to meet demand of a 144 Hz refresh monitor, etc...
Most of today's games have a decent amount of CPU load on them, some more than others, of course...
Let's instead check that your cooling is adequate for an 80-85% CPU load (in overall processing load, not in direct correlation with 'CPU usage' in task manager, as would be common under gaming scenarios... (no game will ever generate Prime95/small FFT sorts of loads/temps)
So far you've not listed any actual problem noted, so much as a possible 'are my temps too high for 'x' usage scenario'..
Just run CPU-Z/bench/stress CPU for 20-30 minutes...if temps at 65-75C, you are fine....(load in task manager will be 100%)
BTW, pumps can degrade after a year or two usage, as pumps get contaminated with sludge, gunk, corrosion, etc...; this would cause temps to gradually rise over the 18-24 month period, sometimes culminating in complete failure, sometimes just degraded temps...
Is your GPU perhaps only a GTX1050/1060 or RX570 class, easily saturated at 1080P with high levels of detail/texture/filtering?