Hi @KyMidd,
Welcome to the Auth0 Community!
I didn’t see anything upcoming about an API field for the Salesforce Domain. I’d recommend submitting feedback about this. Please see this guide: How to Submit Product Feedback or Feature Requests
Additionally, we accept pull requests on Terraform here, if you’d like to submit one: Pull requests · auth0/terraform-provider-auth0 · GitHub
Thanks,
Mary Beth