For user linking, is it possible to do many to many linking? Like after a user signs with a social they can then select which user account to log in with?

Hey @nikron5155 in general, it is possible to link an account with a primary user. And you can link any number of accounts with a primary user. However, two primary users can’t be linked to each other.

but a primary user could be a part of multiple tenants?

yes

another question - how do i create machine to machine tokens? can I create the with preexisting secrets and names?

Not pre existing secrets. See our microservices docs