Solved
I managed to answer my questions on my own, I was completely wrong.
- there is just one
config/server.jsat build time - one has to build once, the admin panel is just a static HTML app without any additional config, that can be deployed anywhere using the API
From my perspective the docs are not very distinct here:
After running
yarn buildwith this configuration, thebuildfolder will be created/overwritten. Use this folder to serve it from another server with the domain of your choice (e.g.http://yourfrontend.com).
It contains any required information and I had read it many times, but I frequently missed its importance.