I just installed PA on Linux and it looks very nice. However, the font size is so small that I can barely read any of the in-game buttons (the main menu, however, is readable enough). My resolution is 1080p on a 13" screen and the main menu doesn't allow me to select a different resolution. But that's okay 'cause the resolution doesn't seem off, only the text does.

Distro: Deepin 20, based on Debian Stable 10
GPU: Intel UHD 620 with newest Mesa drivers
Resolution: 1920x1080

Is there any way to increase the in-game font size so that I can actually start playing this otherwise nice-looking and interesting game?

It's supposed to be K and + but neither work for me on Linux. Try it out, good luck!