I think the problem may be due to screen zoom in or zoom out use Windows + or window - to solve the problem may be it works for you!!
Focus mode problem

Ever find a fix for this because it's happening to me now. I've tried everything suggested above already. It's not terrible but normally the board gets moderately bigger not slightly smaller and just remove the screen litter on the right. Help please...

Yeah focus mode is broken since several days. The screen size doesn't change and those little column of overlay buttons then get superimposed on the board. It just doesn't work. I thought its because I'm using Firefox and chess.com perhaps doesn't test with Firefox but if others are having same problem then its probably something they need to look into...
Please help me, my focus mode is smaller than normal mode. What is wrong? Also the resize button won't work.