Use a bit of super glue, just a tiny amount. The buttons are cheap and easily replaced when you want to get rid of this vinyl.

GTA IV was terrible optimized. I tried it on my modern desktop with 3800X and 3070 and was barely getting 60fps without any mods (with mods it was getting way better while having far better visuals). I was able to get GTA IV EFLC to run at constant 50fps with graphics mods on my Steam deck.

I tried, same behavior. It works only once.

I had a similar issue and tried fixing it with a small plastic part between button and bumper but this didn’t help. I found out that the button was bending back a bit because it wasn’t placed correctly. It was like 0.5mm above the pcb instead laying directly on the pcb. So I sent the deck in for RMA and they fixed it for me. They also were very thankful for my photos and research I did.

If you’re out of RMA you could take a look if there’s a gap between pcb and button. If so, you need to desolder the button completely, clean the pcb from any excessive solder and resolder the button while pushing it down to the pcb.