How do I make an alias my default email address?

How do I make an alias my default email address?

Hi,
I have the email address ( Stephanie@audacious-faith.com) under which I set up the account.
I have an alias ( stephanie@paintyourstory.studio) that I also use.
I'd like to make the paintyourstory.studio email my default email address. How do I do that? (Meaning, I don't want to have to choose it from the dropdown menu each time I use it - which is multiple times/day.)

Thank you!