I have 2 lg exalts which both have the same issue: the keypad is somewhat messed up on certain numbers sometimes it will press too many numbers even though it was only pressed once, and some don't work at all at random times.
Anyone know if there's a way to replace the board that receives the button pressing from the rubber keypad?

Look on global parts direct they make a new keypad which I don't think is a problem, rather the white sticky Keypad.

MXRJR https://globaldirectparts.com/oem-lg-exalt-lte-vn220-keypad-pcb-adb74878101/

I just changed this on a phone with similar problems and it seems to correct the issue.

Unscrew the back remove the 6 screws, then open the back cover remove the ribbon cable and take Off the old sticky keypad and put on this new one. But make sure you all line the new sticky keypad exactly to the PCB board.

Myi Can i swap one of these keypads from another phone i have?

MXRJR You can, if the other phone is working. Though you'll need to pull off both sticky parts togther. As it does separate. Or spend $3-4 and put a brand new one.
The pad consists of two sticky pads.