I experience it exactly like you.

I need some time to recover to get my brain functioning again. When I finish my 8 to 4 work day of average intensity (as in not exceptionally stressful or busy), WFH I'm with my kids, there are a lot of things I can't do until I have some rest. You mention hangover, perhaps. Is more like waking up after only sleeping 4 hours.

When the kids are on bed and the house jobs are done, say 9pm I can have a shower and I may be 80% to do any intellectual activity. Sometimes, as you say, may be watching a series or something like that; definitely not rockets.