Multi-cities on CMS Wordpress?

Question

CMS

Tell me the correct solution to the problem of a long-distance site on CMS Wordpress.
Task:
1. Create a long-distance site, so that each city is in its own subdomain [city.site.com].
2. User registration must be done once on the site [site.com].
3. By placing objects in the admin panel, you can select its location (city).
4. Objects on the site are displayed in the [city.site.com] subdomain, according to their location (city).

Answer 1

Option 1. Network + plug-ins for pass-through authorization.
Option 2. Cities are separate "headings" of an arbitrary type of posts + a plugin for placing them on a subdomain.
These are the simplest, and certainly not the only options, but even with these it will not be easy - that's for sure.