Power switch on MacMini

Yes, we have been leaving our Mac mini's in stand-by mode for years.

If auto computer sleep creates a problem, the choose "Prevent your Mac from automatically sleeping....." and sleep from the Apple dropdown menu or just sleep the display(s).

Leaving the Mac in standby when not is use is fine.

It is recommended to restart the Mac at least once a week to allow the OS to do cache management and other software housekeeping chores.

No, it’s passé/old-school especially for later Macs that complete powering up in less than a minute.

Shut for long absences and overnights and use these settings to disable while in use: