OpenHAB3 MQTT Configuration with Text Files on Windows 10

That’s just a fork of the link we provided in the third post in this thread - what improvements does this fork have?

Please reformat your last post to use code fences, then we can start looking into it.

Probably also worth describing what this means:

Do your openHAB logs show anything useful? Be aware that when using files openHAB sometimes fails to register changes on save (at least on Linux). To remedy this you can do this.

It is unusual to use a leading / in a topic - check the best practices on this page. Are you certain this is what you need?