Falci: but the keyboard can be a bit of a nuisance to make work if you don't put it on a table or other perfectly horizontal surface.
Trooper1270: You mean it won't pair with its Bluetooth dongle unless it's on a solid horizontal surface ?, how strange...
Oh, no, it pairs alright. I can even plug it in a Raspberry Pi 3 with Retropie installed and it works flawlessly.
The thing is the keyboard doesn't have a power button. So, my guess, is something inside it apparently tries to predict if it is in a "usable position" to distinguish between being carelessly moved around or being actually used.
It doesn't have to be perfectly horizontal, but the more, the better. I only found out because I generally use the keyboard on my knees, sitting in the sofa in front of my TV which normally has my laptop connected to it. So, a lot of times I had to push my knees a bit high because the damn thing would stop responding (and I'd get mauled around in Doom or Cyberpunk 2077 or whatever).
So I've began using the feet in the back of it to raise its angle a little bit on my knees and it improved a lot, though it's not perfect.