App to manage processes of not-currently-switched-to accounts

I use two user accounts on the same Mac (2021 MBP), and use fast user switching to jump between them. While in one account, processes in the other continue running. I’d like for some of those processes to continue running, so fast switching is the right thing to do here, but I’d also like to automatically suspend other processes so they don’t affect battery life while in the other account, and ideally reduce the load on WindowServer.

Is there a utility app that can help me with this? I’ve had no luck searching so far.

If not, has anyone come across a good resource for safely scripting suspensions and resumptions in this way with kill -STOP? (And am I correct in thinking that suspending with kill actually improves battery life? Is there a better scripting method?)

I believe LaunchControl can configure the user group or user that controls whether a daemon can run or not. Not sure about agents.

LaunchControl is very powerful, and is a bit like running thorugh a balloon store wearing an Edward Scissorhands costume. So be careful.