Medium format enlargers aren't all too big. Beseler is kind of big, Omega is much lighter. I don't know the good brands in Europe. You want a good lens which you may have to purchase separately. I use a 80mm componon-s for both 6x6 and 35mm. El-nikkor and Rodenstock are great too.

The other consideration is the light source. Cheap will be a bulb and condensor setup, which tends to show dust more easily but are simple and bright. I use a color (dichroic) head to print B&W which is a diffusion light source, and I can adjust contrast with the color dials when using variable contrast paper. You can get good quality for a low price, perhaps not minimal price, but still for a very good value as there is an over-supply of used enlargers.