Hi,
I think I have fixed this issue, I've tried it on a 1280x720 and 1366x768 screen and it was working correctly. You can download the "A Sacrifice (itch Spooktober Jam 2021) v1.0.1 Hotfix.rar" version and it should work correctly now. Thankfully it wasn't as bad as I was afraid of, I just had to change the UI scale from "Constant Pixel Size" to "Scale with Screen Size" and while switching inventory panels had to get the required number from current screen resolution instead of using hardcoded 1920 pixels. I was sliding the buttons 1920 pixels left/right, now I'm sliding the Panel that holds the buttons to "Screen.currentResolution.width" amount of left/right.
Have fun!