Project moved to Unity 2020 from 2017 using much less ram, less CPU, but performing much worse

I have been trying to find a cause for this peculiar performance drop and would appreciate possible suggestions. After moving the project from 2017 unity to 2020 unity. Projects Ram usage has decreased by at least a third, CPU usage by 10-20 percent, sometimes more which has started to bottleneck the GPU, Trying to increase or maximize the use of the CPU and return the ram usage back to normal to remove bottlenecks. I am curious what possible tweaks or changes could address this problem. I am working on this game not on the engine side of things, but have been looking for solutions to suggest to our tech department. Found some posts previously about porting older projects performing worse, but nothing specifically about lesser resource usage, which seems to be our main problem currently.