Problem with registration flow

Hi ALL
Currently, our website is integrated with Salesforce Sales, meaning all users accessing our site are registered on Salesforce. The registration process is entirely developed on this platform. During registration, after entering an email address, a one-time password (OTP) code is sent to the user. This code must then be entered to validate the email address.
The issue arises from the fact that this implementation does not allow Salesforce to automatically recognize users with a ‘verified email address’. According to our suppliers, this is only possible through an alternative implementation that, instead of sending an OTP, sends a link which the user must click to proceed with the registration.
This is causing difficulties as we wish to implement a ‘passwordless’ login system based on a code, which is only usable for users with an email address recognized as valid by Salesforce. However, as one might deduce, most email addresses are currently not recognized as valid by Salesforce.
I would like to know if there is a Salesforce procedure to classify all these email addresses as ‘valid’

Thank you for you support

best regards
riccardo