Keep it. You can register and manage multiple accounts. You should def. be posting out of @muellershewrote.com. You might add an account for every domain you manage, like @dailybeanspod.com.

You’ll be able to manage multiple accounts, both @arpon.basuandgodin.com and @arpon.theathletic.com

Same goes for The Athletic. In the near future, they’re going to change their handle to @theathletic.com. Writers, like yourself, will have their custom handle @arpon.theathletic.com.

Relevant section for you:

I just did this for my domain.