I actually had this problem come up recently myself.
In my case, it turns out my ISP
removed a wifi mode from my router with an update I didn't ask for.
I used to run my 2.4ghz network in 802.11 b/g/n mixed mode with channels bandwidth set to 20/40, which my Wii supported just fine. Comcast updated to some "MyXfi" bullshit about a year back and I didn't think much of it aside from "fuck why is it so hard to forward ports now for computer games ugh"
Come 2023, now, randomly I go to use USB Loader GX and it hangs on init network, which I had turned on by default.
I've found my router no longer supports b mode at all, only 802.11 g/n, which seems to be the source of the vWii no longer being able to connect, and I'm also no longer
allowed to change the fucking router settings for any of that.
I had to set up my repeater that I use for NDS wifi games to allow my Wii U to connect now instead, because the repeater supports b/g/n still.
point is, your problem is most likely your Wi-Fi connection, especially if your Wii U works but the Wii mode doesn't.