Hi,
If it still not working by setting up the Azure DevOps PAT inside the Administration → General Settings → Pull Request → Integration with Azure DevOps Services → Personal Access token field, there’s no other way to make it work. Since for us, technically, the organization should be created from a identity provider “where you code is”, so in your case, with an Azure DevOps account. We don’t support (maybe yet) those multi-purpose organizations.
HTH,