Trimui Smart Pro with broken R1/R2 switch

I bought a used Trimui Smart Pro that had some physical mods on it (a fan and heat sink), but the owner failed to mention the R2 button was totally broken.

I opened it to take a look if I was able to fix it, and I accidentally bridged the button with the R1 while trying to install another button (which also failed because it was too big).

Which button switch can I use for this? Is this salvageable at all? The device turns on and plays as normal, but the lack of this button bothers me so much.