I had been facing the same issue as you. The advice of @chh_68 helped me get around this issue. Please follow these steps.
- Uninstall Uphold app after clearing the app cache and storage.
- Go to verify wallet in Brave mobile browser and continue to verify and authorize Brave.
- Note that this time it would open in Brave only and would not give you the options to open the verification and authorization in either Chrome or Uphold.
- Go through with the authorization and voila.