The machine does not have to be heavy but has to be extremely rigid. Which is a contradiction in a way as typically they are connected. The way to do that is forget everything else and designs all from scratch. And use oversized bearings and linear plus ground ball screws. It needs only 2 axis plus rotational.

At the end of the day the depth of cut here is only 0.5mm at the most. And finish is what matters. I am quite sure that could be achieved under 1000kg. I just don't get where they put that steel, now i looked and chinese machines are 2.8t