Hello Felicia,
Good day to you and thank you for your post in Microsoft community.
We do understand your concern here but as this sole admin account locked, so you need to contact Data Protection Team via Phone support only. Also as we are from community team, we don't have such resources to reset admin account.
Further for call support, different country have different process. Below sharing process, you can check it. Also here provideing all call support link, based on your country, you can check
https://support.microsoft.com/en-us/topic/global-customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2 and
https://learn.microsoft.com/en-us/microsoft-365/admin/support-contact-info?viewO365-worldwide
For some countries, while there will be around 30 seconds opening like something "you can visit link....." But you can ignore this opening and wait till the option, then "1" as business email user, "1" again as technical support.
For some countries, it will be auto conversation like: First, when I called the hotline and it will asked what kind of issue that you're troubled in.
I replied: authenticator
A: What kind of product that you're using?
B: Office 365 for business.
A confirmed: Whether education account or business?
B: For business
A: Are you administrator?
B: Yes.
A: Do you have the other administrator of your organization?
B: No.
A: Do you need a .... service request?
B: Yes
Hope this may offer some instruction for you.
Thank you.
Ankita Vaidya