I need help setting up a Microsoft work account and I want to make sure I don’t break anything.

Hi, I need help setting up a Microsoft work account and I want to make sure I don’t break anything.

My situation:

• My company email runs on Google Workspace. It must keep working, I cannot lose email.
• I already have a Microsoft Entra tenant (I created it to register an app for the Microsoft Advertising API). My login there is currently a personal / Google-based account, not a work account.
• I need a real work/school account so I can join the Microsoft AI Cloud Partner Program and complete publisher verification. My personal account keeps getting rejected and signs me out in a loop.

My questions:

1. To get a work account on my own domain, do I add my domain (e.g. example.com) as a custom domain in my Entra tenant and then create a user with it? Is that the correct path?
2. If I verify the domain using a TXT DNS record, will that affect my Google Workspace email in any way? I want to confirm that adding a TXT record (and NOT touching my MX records) leaves my email fully working.
3. Can I do this on the free Entra plan, or do I need a paid subscription/license?
4. Once the domain is verified, what are the exact steps to create the you@example.com user and give it admin rights so it can be used for Partner Center / publisher verification?
5. Is there any risk that my domain is already “claimed” in another Microsoft directory that would block me? If so, how do I check and fix that?

Please give me step-by-step instructions. Thank you.