Why won’t my iMac 27” turn on?

If your Mac doesn't seem to turn on after you press the power button, follow these steps.

1. Make sure that your Mac is connected to AC power. If it doesn't have a built-in display, make sure that your external display is connected to power, connected to your Mac, and turned on.
2. Press and hold the power button on your Mac for at least 10 seconds, then release.
3. Every Mac has a power button. On notebook computers that have Touch ID, press and hold Touch ID.
4. If you see no change on your Mac, press and release the power button normally.
5. If your Mac now turns on but stops at some other screen during startup, follow the steps for when your Mac doesn't start up all the way.

If your Mac still doesn't turn on, please contact Apple Support.

This is a long shot but see if the machine can boot up into Target Disk Mode. If it does then there's hardware damage/failure somewhere but not with the drive be it SSD or HDD. That will help narrow down the problem.

1. Check the cable on the back of the iMac to ensure that it is full inserted.
2. Test the iMac plugged into a different outlet in your home or office.
3. Test your original cord plugged into a 110v to 220v adapter.

Damaged in transit maybe..

are you even getting any signs of powering up