Interesting. I also use UniFi and connected mine fine to my UAP-nanoHD.
If you just wait, does it eventually give you an error message? How long have you waited? Did you try connecting it on the 5Ghz band instead?
The first time your controller connects it will have an update to download, but it sounds like you're not reaching that point as it specifically says it is updating.
Here is the general support article for setting up the controller in case anything in there might help you:
https://support.google.com/stadia/answer/9578658?hl=en&ref_topic=9495415
Interesting. I also use UniFi and connected mine fine to my UAP-nanoHD.
If you just wait, does it eventually give you an error message? How long have you waited? Did you try connecting it on the 5Ghz band instead?
The first time your controller connects it will have an update to download, but it sounds like you're not reaching that point as it specifically says it is updating.
Here is the general support article for setting up the controller in case anything in there might help you:
https://support.google.com/stadia/answer/9578658?hl=en&ref_topic=9495415