Email aliases supposed to work for multiple account registrations

Hey ,
Email aliases are meant to be treated as different email identities.
So for example if you register as a user with oliver.wolff@kinde.com and you register another user with oliver.wolff+123@kinde.com, they will be treated as 2 separate email identities.

You can have the the 2 email identities against the same user if you like - see here on how to have multiple email identities against a single user.
Or you could have 2 different users each with their own email identity.

I could register x amount of accounts for the same email

Are you able to elaborate on what you mean here?