For another test, do you have an old router (or access point) lying around collecting dust because it does not support the latest wifi protocols? The ESP8266/ESP32’s do not need that, so you could for testing purposes only setup a separate network with no internet access. Just the router plugged into the wall, and a PC connected via network cable to configure it.
You can verify it is not WLED’s fault if it successfully connects and can be controlled using that same PC, and maybe a smartphone over wifi.
I read somewhere there is a setting in some routers to block LAN / WLAN multicast which seems to affect WLED (at least on some routers).
This little test can rule out a lot of things.