As mentioned by Microsoft and strongly supported by the community, account creation using Azure AD is recommended. Following this path, however, I think it is not applicable to our use case for Power Pages.
We'd want our account creation to be by invitation basis by first filling out a separate form, then notifying our team to send out an automated invitation email. With this, we can assign the accounts initial account creation of the users.
I'd like to ask why is it recommended to use Azure AD, and could the Azure AD method be used to comply with our requirements? To add, I followed this community post from 2021 as a guide (Solved: Confirmation email on Registration - Power Platform Community (microsoft.com))