I got a Rapoo keyboard for free. Since I consider it a no-name brand I'm not at all surprised that it turns out to be insecure (perfectly matches my expectation

I got a Rapoo keyboard for free. Since I consider it a no-name brand I'm not at all surprised that it turns out to be insecure (perfectly matches my expectations), I'm rather surprised that the author even audited them and that they even attempted to secure the communication a little bit. So my intuition that generic "2.4GHz" communication is insecure has mostly been proven right. Now what about Bluetooth keyboards? Can they be considered secure?