Hi there,
I am just starting to deploy HomeAssistant.
In order to connect a couple of Bluetooth thermometers, I was wondering if I use a single USB-Bluetooth dongle in my server, or a a ESP32 based bluetooth proxy.
The question is: If I connect the thermometers to the ESP32 based proxy, do I still require some kind if bluetooth dongle directly in HomeAssistant server instance?
Thank you for clarification :-).
Kind regards
Short and long answer: No
Short thanks :-).
So, to avoid all misunderstandings, as the documentation seems to leave that out (or assumes it is clear):
The sensors connect to the ESP32 proxy via bluetooth, and the Home Assistant server to the ESP32 device(s) via wifi?
Yes (I have to add some text for the answer to be 10 chars 
)
Ok, so if I have an Esphome BT Proxy device (POE) on one side of my house, and a BT dongle attached to my server on the other side, what happens to passive bluetooth events that come in from the dongle after I attach the proxy?
ProTip: “The devices connected via the dongle should still work fine” is NOT the right answer. Finding out why is my real question. Once I connected ESPHome and flashed the proxy, it started picking up all the passive device messages near it (yay!) but instantly the messages coming in from the dongle on the server stopped. I have all these devices (xia flower sensors) discovered and working in the Xiaomi BLE integration. There is a BTHome integration as well, but none of the problematic devices are using it (BTHome doesn’t support the Xiaomi myflora protocol nor does the myflora fw support BT Home v1/v2)
How do I see bluetooth events on the bus and know who consumes them?
Debugging recommendations?
They keep coming in, just like normal. HA doesn’t really delineate between BT dongles and BT Proxies.
BTHome doesn’t have anything to do with BT Proxy, it’s just an integration like any other. Your plant sensors using the Xiaomi integration will continue to use that integration, regardless of whether they get picked up by a BT Proxy or a BT dongle connected to HA (I have almost 20 of the MiFlora sensors and lots of BT Proxies as well as a BT dongle). The BT Proxies send all the data they see and HA sorts things out automatically.
Maybe elaborate on your issue?