Playstation power button not working

I'm trying to become a bit of a hobbyist In repair and my friend has given me his ps5 controllers to try and fix. Two had stick drift which were very easy to repair. But this third controller is driving me insane. I have taken it to pieces. Cleaned everything yet the PS button in the middle never engages. I've cleaned all the contact. Checked the motherboard still nothing. I changed the battery which showed the charging light working but the PS button still didn't work. Is there a way to diagnose it? (every of a button works fine. I used steam controller test which is very good for me. It shows everything working fine except the PlayStation home button)