How it works is confusing to many people.
As Docker containers, I’m running HA core so I fired-up ZwaveJS2MQTT to see what it did and also added the integration to see it. But I deleted the integration and stopped the container for now. ZwaveJS2MQTT did have the ability to adjust parameters it seemed, but I didn’t did into it too deeply.
ZWaveJSserver get installed if you are using HA supervised and install the integration via the supervisor, right? And you can’t set anything with it, or can you do settings via HA in the developer tab?
Right now, I’m using OZW and it works without any issues at all for me, so I have no reason to switch yet.