OpenMQTTGateway runs on ESP32/ESP8266 depending on what kind of gateway you chose to set-up. It also allows for RF, LoRa, IR gateways, whereas Theengs Gateway only decodes BLE devices.
And yes, OpenMQTTGateway also has Home Assistant integration and discovery, like Gateway does.
Just think of Theengs Gateway as the BLE side of OpenMQTTGateway which doesn’t require an ESP32, but can also run on your HA device.
No need you would have to change to OpenMQTTGateway for this, as showing the advertising/advanced data is also on the roadmap for Theengs Gateway. It would have just been helpful to investigate your above issue.
If you have an ESP32 lying around you could try it with installing esp32dev-ble on it.
I think your work will be very useful.
There are infinite application of a BLE to MQTT gateway that is also an Home assistant’s integration.
I’ll wait for your investigations and for a major release available.