There's just a bug that I encountered (Anki 23.12.1), maybe it's a conflict with other add-ons I don't know, but the dialog window to import a PGN file has a huge width by default (it extends past my screen's width), and when I attempt to resize it it seems to crash. I have to drag the window manually (without resizing it) to see the right end of the window and the button to import a file.
I fixed this by adding self.setFixedWidth(1000) on line 46 of the dialog.py file. It's been a year since I touched PyQt6 / PySide6 so I kinda forgot everything, there's probably a better way to do but I don't see the need to have a resizable width for the dialog box so I didn't bother to look for a better fix.
A reviewer reported the following: