Hello Sebastian.
Sorry I didn’t mention that using KESTREL__ENDPOINTS__HTTP__URL does really override the hardcoded port, but I gave the suggestion for using hardcoded ports to follow the app native way, or use appsettings only so the binary version could work and Squidex will stay docker-ready.
Also one problem with KESTREL__ENDPOINTS__HTTP__URL is that it does actually change the port but it make it only reachable via local network (Linux way of things) not exposed to www unless I use a wildcard Url http://*:80 first time I ever done that) and I don’t know if it is safe or not, but even using the server’s ip it doesn’t expose to www.
Anyways after a second thought I found this a single user issue and should not change the code.
You can just link this thread in the documents under (Running Squidex with Kestrel without docker).
Thank you so much for your time 
I hope the best for Squidex and I will surly use it in production.