I have a vague recollection that Glyphs used to remember the order and sizes of the columns in List View after closing a window. Not sure if this ever used to be the case or if Big Sur broke this functionality.
Builds 1352 and 3053 in Big Sur 11.1.
Glyphs does remember the column sizes and order on my machine. (Glyphs 3.0.2 (3053), macOS 11.1 (20C69))