Thanks for getting back to me!
If you cannot set the exact record, you need to either reach out to the current owner and ask them to transfer the domain to your team, or we can follow our internal domain ownership process.
The latter involves asking the current owner to create a custom TXT record on the apex domain so we can validate ownership. Once we verify it, we can delete it from the old team, and you can add it to your account, skipping the addition of _vercel in your DNS records.