The first problem is Garmin Connect on phone and Garmin Express on PC don't allow me to add a hidden network (where the SSID) isn't displayed - a pretty standard setting on many WiFi networks. So showing the SSID allowed me to connect, but once I hide it again the Enduro 3 is unable to connect to WiFi.
This is an extremely annoying lack of basic feature and settings. There should be the very fundamental option under "add network" to be able to select "connect even if network is not displaying/broadcasting".
Also, even though this setting didn't exist for my Fenix 6X and Fenix 5X either, they were both still able to connect to the same hidden WiFi network without any issues....
Please fix this Garmin.