There are also some waterproof ultrasound distance sensors you could use

Agreed, the shielded modules can run at full power without any problem

Rfm69 adapter still requires some soldering

Just use mqtt client

That's still on the cheap side, it is still probably a clone. You can consider going with rfm69 radios, they work better

I think it is more of a BT gateway to connect some of their BT devices

Yes, that was Rev 9, but the sketch would work with anything you have

Never seen a single device using it

Unless they find a way to make a mesh network out of Bluetooth, it will not get much success imho, or you have smart devices like xiaomi that have a Bluetooth gateway on board but that would add more complexity

Yes, I have both radios on the same raspberry.