As most MS’s advisors suggested, make sure you have the latest firmware to all components. Then try to narrow down the problem by using Event viewer, see what you can spot any misbehavior warning or error then go from there.
If you see something along this line.. “processor is being limited by system firmware” then most likely hardware and software are not being at full potential.
As to my system; Updating bios firmware kind of mitigating the issues but problems still lingered (a lot less). Not until I installed evaluation copy 19013 which supposedly should be released as 20H1 then all issues are disappeared. I don’t want to speculate, but something seems different in which they are being compiled.