Broken screen, phone won't turn off - how do I repair?

I am about to attempt a screen replacement on my pixel 5a. However we can't get the sceen to turn off. No matter how long I hold the side button, the phone still rings if I have someone call it. The screen is completely destroyed so there is nothing to see or select when trying to power down, but just holding the button long enough SHOULD turn the phone off.

I don't know if I can repair the phone if I can't get it to turn off, and this phone has such a long battery life it could be a week before the battery dies. It's currently at 29% and I can't even remember when last I charged it - I was keeping it charged do I can get texts on my laptop.

Well it looks like I get to answer my own question... it's power + volume down you have to hold to turn it off. So phone is off now. :-) Hope this helps someone else.