Hi
It doesn't look good when some of the solutions have caused issues. I've sent a feedback to Apple, hopefully the more of us send a complaint the more likely they will to change it.
"If you need to stop this behavior--to clean the keyboard, for example--you can force a shutdown once.
Press and hold the left Control and Command buttons with the right Shift button for a total of 7 seconds. Without releasing them, press the Power button and hold them all together for an additional 7 seconds. Your Mac can only be powered on by using the Power button.
Unfortunately, there is no way to disable this permanently."
https://apple.stackexchange.com/questions/395453/how-to-prevent-macbook-pro-from-powering-up-by-pressing-any-key#:~:text=Your%20Mac%20can%20only%20be,way%20to%20disable%20this%20permanently.