Solis or Avenger compact tractors experience?

No experience of those brands. But if you can get a 135 or a 240 it's still a stronger tractor than a garden tractor in my view.

You should be able to buy one for a lot less than 12k.

Parts for the vintage tractors named above have been available for the past 50 years without issue and will probably be for the next 50 too, could you say the same about some of these new budget brands?

More maneuverable too if there is tight spots, but might not suit some operators if they struggle for maneuverability themselves getting in and out except for something like a JCB robot with boom on one side and a door on the opposite.

Full disclosure I work with Solis Ireland. I want to make the point that the number one selling tractor of any brand in Europe is the Solis 26. This is outselling any other model from any other brand. There are tens of thousands of these tractors on the market and this number is increasing. Parts will most certainly be available for Solis in 10,15, 20 years time as there is good business in it; just like any common brand models mentioned previously like David Brown 885 or Zetor 3511.

which model ? 2054 is just about capable of lifting bales of silage