PS Button not responsive, Controller only works when connected to PC.

TLDR: See title, I have replaced battery, cleaned motherboard and conductive film with alcohol. Nothing has changed, every button works except the PS button and it only works when plugged in. I am just wanting to know other possible solutions or causes while I wait for a replacement conductive film.

So some context, I have aps5 controller which I had left at my parents place for a couple months, to finally come back and retrieve it to find that (at least) the left analog stick chewed a bit (suspect was my niece) and found a few oily marks.

I have brought it back, cleaned it up and replaced the thumb-grip and the controller is all but functioning! at least, I thought it was until I noticed that it only works when connected to the PC. Doing some research, I assumed it was a faulty battery and have now replaced it with a larger one! Controller still functions but still, the problem persists!

I do some more research and it seems the issue I thought I was having all lead to the same solution, which was a battery replacement. It wasn't until I did some button testing to find that the PS button was unresponsive, both via steam and the gamepad test website. Now knowing this, I did some additional research and found that the likely culprit is a faulty conductive film, which I have now ordered and await it's arrival.

What I am asking now, the real reason for the post, is whether there could be another solution? As of now, controller still works when connected with wire to my PC, I don't own a PS5 to do some troubleshooting there if there are any. Testing the controller with the new and original battery still shows that the PS button still is unresponsive. I have cleaned the conductive film several times, and even the motherboard to where it connects to, but still nothing has changed.

I guess I just have to wait for the conductive film to arrive and replace it, I have even looked that the little foam pad could also be a culprit, that if it is too squished it could be causing little connection, but that would be so weird for the PS button to be the only thing that didn't work, right? If either of those don't resolve the issue, I guess I am stuck with a wired controller, with a useless battery upgrade smh. BUT PLEASE, what could also be the issue here?