So, I've found in the warehouse this console I didn't even remember I had.
It's a SGM Regia 8, a tiny 8 channel lighting mixer.
Big problem, it's not DMX. It uses 0-10v.
I've found online some converter 0-10 to DMX, their price range is €80/90, which is probably 10 times more the value of the mixer itself.
You don't mention what you wanted to control with the desk? These little boards tend to just be hung off a dimmer pack or two in very basic setups like small schools.
There are plenty of dimmer packs that either use analogue or even DMX featured ones that have a 0-10V input as well.
As you've found already, it's probably not economical to try to adapt it to DMX with a converter box.