Great thanks for joining this topic.
Although, it is not what I want. Because I believe there should not be border for B2C shop.
As to sharing user account, Please check this one plugin: GitHub - themarcusbattle/press-sync: The easiest way to synchronize posts, media, users and more between two WordPress sites.
And I think we can find a way to sync the users across the multisites in each countries if it is a reasonable method for a global commerce site. And the method should be trigger or auto cron by security api, but not by a plugin.
The most tough and real question is how we can use one multisite for all countries(like fr.oursite.com, uk.oursite.com, and improve the performance for every local market, it is enough by Cdn? Maybe not…what is the method then?
Another task is how to make a subsite support directory site so that users(shop owner) can register a site, so the shop owner sites will look like this way:
Fr.oursite.com/Nike
Uk.our site.com/tommy
I found this plugin works well although it is outdated:
I understand it is not easy, and the method by plugin is not an great performance, but the above plugins proved that it is possible if we custom develop based on Wordpress, maybe CC? Because I do not know what was changed from Wordpress to CC.
Anyway, I will keep looking for a right approach, and appreciated your sharing ideas, comments, suggestions, and even nagtive advice.
Thanks all, and happy on CC.