The org.bluez.Error.NotAvailable message shows up in this thread:
https://forum.tinycorelinux.net/index.php/topic,25245.msg161269.html#msg161269
That thread deals with a bluetooth keyboard, but it might contain some ideas
that apply to your situation too.
This was helpful (and embarrassing as I read that thread before but I did not realize there was second page).
I tested it with a bluetooth keyboard and it worked, except for Ctrl-key.
Then I was able to extract joydev.ko and copied it to system. I also added a line to modules.dep so that modprobe could find it.
After modprobe uhid, uinput and joydev the game pad connected. Yeah.
After startx, the joytstick worked like a mouse and the main button as mouse-click. Great!
Thanks very much.
Next step is to figure out pybluez and pyserial, but that is for an other post....