Impossible to reset SMC (holding left Shift-Control-Option )

Yes, Dan, I did. Tried both. No avail. Mac reboots after 3 secs. Brand new.

Found the correct answer here :

https://www.macworld.com/article/2881177...

* Laptops with the T2 chip: Shut down. Press and hold the power button for 10 seconds, then release it. After a few seconds, press the power button to turn on your Mac.

* If this doesn't reset the SMC, shut down. On the laptop keyboard, press and hold Control-Option-Shift (your Mac might turn on). Hold these keys for 7 seconds, then press and hold the power button. If your Mac is on, it will turn off while you hold down the keys for another 7 seconds. Then release the keys, wait a few seconds and turn on the laptop.

@Vlad Hans - Thats what the Apple T/N stated ;-}

Reset the SMC on computers that have the T2 chip

If your Mac has the Apple T2 Security Chip, follow these steps. If you need help, contact Apple Support.

Notebook computers with the T2 chip

Before resetting the SMC, try these steps:

1 - Shut down your Mac.

2 - Press and hold the power button for 10 seconds, then release the button.

3 - Wait a few seconds, then press the power button to turn on your Mac.

If the issue persists, follow these steps to reset the SMC:

1 - Shut down your Mac.

2 - On your built-in keyboard, press and hold all of the following keys. Your Mac might turn on.

Control on the left side of your keyboard

Option (Alt) on the left side of your keyboard

Shift on the right side of your keyboard

3 - Keep holding all three keys for 7 seconds, then press and hold the power button as well. If your Mac is on, it will turn off as you hold the keys.