Agreed -- I only do 2 active things at a time, and maybe something third that is long-running in the background (like training a model or classifying thousands of files, where I just need to check in occasionally to make sure it hasn't veered off-track).

It's rare that with my 2 active things, they're both busy, since one usually finishes while I'm drafting my reply to the other.

When it occasionally happens that both are busy for the next 5 min, I just get to enjoy the break and stretch my legs and walk to the kitchen or something.