Personally, I'd prefer the system repeatedly prompt the user to restart to apply security updates (of which almost every update contains these days) instead of automatic restarts. It does try to apply those during what it believes are not "active hours", but it is not a perfect system.

Until that happens, consider setting your active hours manually in the Update & Security -> Windows Update settings panel. The update system is designed to avoid automatic restarts during active hours.

You can also pause updates for a period of time as well when you know that you don't want your system disrupted overnight.

I empathize with your frustration around the timing and I would encourage you to file feedback asking for more control over when updates happen.