You can also just flick the "extDecoderEnable":true switch on your current esp32dev-ble version to make it esp32dev-ble-mqtt-undecoded.
They it will publish the undecoded raw messages which Theengs gateway will pick up, decode and republish, even when its own
-b BLE, --ble BLE Enable (1) or disable (0) BLE (default: 1)
set to 0, Theengs Gateway shouldn’t even look and want to try to received any local BLE broadcasts, but only decoding the undecided messages received by OpenMQTTGateway.
Best to watch and confirm how these messages flow like that with MQTT Explorer.