Thank you for the support again. The username "root" does indeed work. I am sorry, I didn't know about this (still a noob, but eager to learn!).
So there is no problem with SSH as far as I can see now.
That is indeed the controller of Xiaomi that I use, it works out of the box and there is no need to swap the buttons. Connecting is very easy and it is almost an exact copy of the XBOX controller. Works very well for me.
Now I am looking for a new challenge; Getting a good controller for Goldeneye for the N64 emulator, but it looks like there is no good controller available (if I search for it) with a good stick. So if anyone has got any tips to get this working fluently, I will be very happy, I still love this game.