This solved it for me: Modern home WiFi is a combined 2.4 and 5 GHz network. I separated those via the App that comes with the Router (basically give the 2.4 GHz a separate name). Connect the EDGE to the 2.4 GHz and the EDGE syncs as expected. Usually modern devices can sort the 2.4/5 GHz networks out by themselves but Garmin seems to have broken this in one of the latest updates.