I was about to order a SLZB-06, but they were out of Stock. That one looks exactly what I want. I never really looked into NodeRed, but normalizing everything before using it makes sense. The SLZB-06 makes the Zigbee Network connections independent from any Servers and making everything going through MQTT makes you independent from any Software that has to communicate with the Devices. Sounds like a lot of flexibility and independence.
That is cool, thank you very much!