Hellow,
am testing a bit UpBGE 0.41, my game worked well if i completely get rid off the bgui part (logic brick that call bgui.main.py)
With my UI i had only 1 problem related to label and font size.
Apparently it can be fixed easily.
So, in upbge_directory/4.1/scripts/modules/bgui
edit the file label.py
Lines 80 & 112 should read the same, like this:
blf.size(self.fontid, self.pt_size, 72)
Grip your axe firmly and chop the end, like this :
blf.size(self.fontid, self.pt_size)
At both lines !
I can’t really say why, what, who, wich universe, but for now it seems working well.
Am using all sort of bgui widgets: progress bars, img, list, buttons, they all looks ok. Themes also works.
For now am not using layout, might be a thing to check.
Hope this helps.