Test New Universal Login template customization through deploy CLI tool

Hello there!

I want to test setting the New Universal Login template through the deploy CLI tool. I have a free dev account and paid production account.
Here’s my tenant.yaml

    - template: universal_login
      body: ./pages/login.html

When I’m doing it through the free dev tenant I’m getting

error: This feature requires at least one custom domain to be configured for the tenant.

This means I have to test in the paid production tenant where I have a custom domain configured. I want to be super cautious about touching the production tenant.

If I create another test Deploy CLI Application configured (not one that we use to update prod) and run a0deploy import against it to see changes locally, any chance it will target the production application?

What is your suggestion if it’s not safe to do it this way?
Thank you!