Essentially my entire suggestion is covered in the title. The reason the default CPU usage cap etc. do not work for me is I still find relying simply on that can result in usage spikes during low intensity gaming causing issues, so for now I choose to suspend all computing during the time I'm at my desk gaming; However whenever this doesn't cause me issues that alone brings my contribution up by huge amounts simply because I do not need to micromanage.

If it were not an option to have some kind of solution that is integrated with other apps/programs, could we maybe have a feature that is "Do not run projects at the same time as (x) application." as a simple easy feature to keep things smooth on my PC?

I'd also like to add, this may already be a feature I'm missing, but the possibility to usage cap your CPU/GPU would be amazing, and I don't mean the existing down-time cap, I mean the ability to use only for example 30% of CPU actively, as this would allow me to play many of my games on my rig, while continuing to contribute to projects even during up time.

I think what your looking for is the "Exclusive applications" option within BOINC.

When BOINC is in the advanced view:
Options -> Exclusive Applications

In that section, you can select what applications will cause BOINC to suspend.

As for CPU usage, have you checked the custom computing preferences on Science United's website?
https://scienceunited.org -> [click on your username] -> Computing preferences -> Show (it's at the bottom of the page) -> 'When computer is in use' section -> "Use at most X% of the CPUs"

Hover over each of the settings to get more details about what that setting does.[/img]