Single Sign on on nopcommerce and some other app

I find that there are several topics on Nopcommerce forum about SSO, some of them are very old and hope currently there is some tested solution.
I have couple of applications, one of them is nopcommerce. I want to have SSO on all this apps.
I can use an external SSO service such as Auth0 or IdentityServer as main SSO service. and change nopcommerce and other apps to force using IdentityServer instead of local user, it seems that I have to disable creating new user, and enable external SSO service.
But if I want to use nopcommerce as main system and all users login to nopcommerce, authorize to use other apps based on local roles on other app, how can I do that?
Which plan is better?

I have successfully implemented a nopcommerce plugin to allow SSO (Identity Server, Azure AD, Azure AD B2C) authentication. PM me for more information.