We recently updated the documentation to make it more clear you shouldn't use the /api/jwt/reconcile endpoint for any identity providers except the external JWT provider. We'll change the application to make the error message clearer; here's the tracking issue: https://github.com/FusionAuth/fusionauth-issues/issues/2074
You should use the OIDC provider and the complete login endpoint. Here's documentation that should help: https://fusionauth.io/docs/v1/tech/apis/identity-providers/openid-connect#complete-an-openid-connect-login
Hope that helps!