M1 Mac Mini's Ignoring autorestart

Hi there, I have 10 M1 Mac minis deployed in an exhibition. For 3 years they ran fine with exhibition power turning off at 6pm and on at 9pm. Suddenly 3 stopped booting after power loss. Now another one. I have retrieved them here an no matter what I do it won't boot after power loss? Any ideas? Have done full wipe and reinstall. Running latest OS. Replaced CMOS battery. Nothing helps. Help!!!

M1 Mac Mini's Ignoring autorestart
 
 
Q