I think part of the exhaustion is that there's no in-between phase from work to home. A commute helps, because I have time to mentally cool down after ending the day. WFH, I get jumped by my kids as soon as I leave my office, but my brain is still working on that software architecture design document.

What helped me was to aim to stop working about 30 minutes before leaving the home office. During that time, just read a book, post on HN, answer/delete emails, all this lighter behavior.