Logging in directly without a password (not via OTP)

I’m developing a website there the users are going to have access to their own data. I’m gonna use a specific authenticator called BankID which is widely used in Sweden, a kind of extern authenticator (as an app in the mobile phone). The user completes the authentication process via mobile phone and we get a success response when the auth process is over. But then I want the user to be redirected to the WordPress user-dashboard just like a user that has normally logged in to WordPress. What is the easiest way to do this?