login into shopify coustomer

[ajangir]

I am using a custom front end for my Shopify store made in React there I have created an option for the user to log in using Google SSO  and get the access token.
I have not found the best approach to do this. I don't want  to use third-party apps  instead I can use node js if required but still I need a storefront graphql API to get the access token for the user