Recover Microsoft 365 2FA Access

I’m locked out of my business Microsoft 365 / Outlook account because I no longer have the authentication app that was linked to the tenant. Standard password reset works, but the two-factor challenge stops me cold, and no verification codes are arriving through any other channel... (Budget: £20 - £250 GBP, Jobs: Azure, Microsoft 365, Microsoft Access, Microsoft Exchange, Microsoft Outlook, Security Auditing, Sharepoint, Windows Server)