PS5 Controller - L2 unresponsive

[SunsetZed]

On my second controller it won't work in games and having plugged it in and tested on https://hardwaretester.com/gamepad it seems that the reason is that the L2 button is unresponsive.

The button feels absolutely fine in terms of tension so I don't think the spring is broken but when I look for videos on how to repair it all I'm finding is spring replacement videos, anyone got any thoughts on what the cause and fix could be and if possible any videos on how to fix it.