Hello Gene Lawin,
Thanks for your question.
The 5 MB backup size is specific to the Microsoft Authenticator app and is not influenced by the amount of available storage in your OneDrive or M365 subscription.
100 accounts are the maximum allowed as well.As regards if it can be removed, I think the best possible place to post this issue is on the feedback portal as Engineers constantly check to see the most upvoted requests:
https://feedbackportal.microsoft.com/feedback/
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola