Architecture for a dozen sites on React JS?

Question

React

The client wanted a portal site on React JS
The portal performs primitive functionality, a news page, contacts, a page for submitting an appeal
Under this, the admin panel is minimized, editing news, contacts, etc.

The site is currently raised on Docker
Nginx stack, postgres, node js backend, frontend React JS/express/node js, for prerender.io robots, various plugins for example Power BI
At the moment, during load testing on resources of 2 CPU and 2 RAM, with a good response in relaxation, it keeps 250 agents
Number of real visits 1-10 per day

I ask for help, it is necessary to understand how to disassemble and infrastructurally distribute this site into several dozen copies for each department, they themselves will administer content, news, contacts and receive requests on it.

What I think:

1. Linux server is Nginx
2. Linux server is postgres
How to share the rest?
For example, separate rendering for search engines
. It's not clear what to do with the frontend, I'm offered to leave everything in Docker and it will be connected to a separate Nginx and Postgres server. Tell me

how best to organize everything else.