ESP32 can't be found as device in MQTT

I want to control two Bluetti AC300 via Homeassistant (running on a Raspberry Pi5)
The first one is directly connected via bluetooth.
The second one should connect via Bluetti MQTT Bridge running on a ESP32

First one works perfect.

The second one can’t be found as device, even though MQTT Explorer found it:

…6730 is the directly connected Bluetti
…9294 is the second one via ESP32

I would really appreciate, if you can help me.

Create a device with multiple sensors via mqtt discovery
Check out the link above.