Setting Up Automatic Power On

Open Terminal on your Mac

Set up the schedule using this command:

sudo pmset repeat wakeorpoweron MTWRF 08:00:00

This command means:
pmset repeat - sets a repeating schedule.
wakeorpoweron - wakes or powers on the Mac.
MTWRF - Monday through Friday (weekdays).
08:00:00 - 8:00 AM.

Verify the schedule was set correctly:

pmset -g sched

This will show you all scheduled power events.

To Remove the Schedule Later

If you ever want to cancel this:

sudo pmset repeat cancel

Important Notes:
Your Mac needs to be plugged into power for this to work.
Some MacBook models may have limitations on power-on scheduling.
The Mac needs to be shut down (not just sleeping) for it to power on automatically.