Given I can have four Gtk apps not in FlatPaks all have different title bars in GNOME proper, I don’t think this will ever work properly.

You have swap, which is pointless in this day and age, and will just burn a hole in the flash and delay the OOM killer doing its work. Look at ntfsresize to shrink that Windows partition down to the minimum. Then maybe image the partitions and obliterate them from the SSD. Use LVM instead to give yourself future flexibility. 1TB NVMe SSDs are so cheap these days they might as well put them in boxes of cereal.