L button not working

Good advice, logical and all. I like logic too, so I did what you said prior to creating this thread and it didn't resolve the issue. I took a clean q-tip, soaked it in a 96% isopropyl alcohol (but not too excessively) and used it to push the button multiple times, so that isopropyl alcohol could make it's way through into button internals and not just outside. I did this, waited about 15 minutes to make sure alcohol inside the L button evaporated completely and then assembled and powered up the console. At first everything seemed fine, until I played a little bit of Hades and the issue came back. So, as I understand, the button is dirty inside and the issue will bother me until I either replace it or find a way to thoroughly clean it somehow. But how? I doubt the isopropyl alcohol can push the dirt out of the button, so it seems like such procedures will have only temporary effect and I'm not okay with that. That's why I decided to ask about button replacement.

Oh, I just realized... It wasn't isopropyl alcohol, it was 96% ethanol. I suppose it can do the job too, but not as effectively.

Regarding screw being overtightened - I don't believe that's the case, since I used the recommended two fingers technique and, to be honest, my fingers are very weak, so I don't think I could have overtightened anything that way.

Furthermore, I just checked the console and the button seems to be working again but I think it's not for long. So, I seek more or less permanent solution instead of temporary one.

I saw left side button boards on Amazon for around 25$ (exactly like the one you can see in step 7 of the teardown you suggested). 25 USD is not that big of a deal for me, so I think a factory assembled option would be better than trying to solder a new button on top of the existing board. Or should I try cleaning the button once again, but with isopropyl alcohol? What do you think? I can buy a bottle. Previously, I just used ethanol alcohol that I had on hand.