What do you mean the org-managed account?
If you mean technical contact (see Image 1), when you request a new Office 365 organization, it will generate an account like this format: YourEmailAddress#EXT#@yourdomain.onmicrosoft.com, you could use this account (see Image 2) and assign related license to use Teams.
Image 1.
Image 2.
If I misunderstand your words, please give us more information to know your real requirement.
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