There is a test version with some Bluetooth proxy support available here; Release Latest Build · seime/openhab-esphome · GitHub
For now it only supports beacon advertisements (device broadcasts data but without any 2-way connection being made with the device). So no need to test connectable devices such as Airthings etc, it might blow up.
I’ve tested it with a the new BTHome Binding and gotten a handful of b-parasite plant sensors up and running via ESPHome devices.
I’d love for someone to test it and give some feedback. There are a few steps that must be taken in order to enable this functionality, so please head over to Github to read the details.