Rituals/habit.

Easily repeatable, no-fail(doesn't matter if you don't do it) routine. Using a ritual repeatedly will eventually signal to mind and body you are in a different physical/mental space now.

Many people like exercise based rituals; walking, running, sports. "walking around the block" was highly suggested as a substitute for the commute during lockdowns. Some walked clockwise to get to work. Anti-clockwise to go home.

Second part is to deliberately not think about work BUT ALSO not have to concentrate hard. You've done/about-to-do a good day, give yourself a break for a moment.

I commute via motorcycle and find the requirement to be "present" enforces not thinking about work.

Edit -clarity