What does switching between businesses cost that never shows up on a calendar?

Everyone talks about the time cost of running more than one thing, an hour here, an hour there. Nobody talks about the reset cost. Going from a staffing call to a pricing decision to a customer complaint isn't three tasks, it's three different modes of thinking, and I always lose a few minutes just remembering which version of me the next one needs.

Some days that reset tax alone feels bigger than the actual work. Curious if anyone else who juggles more than one business or product has found a way to shrink that switching cost, or if you've just made peace with losing a chunk of every day to it.