I used to have a SuperUniti, which I enjoyed very much with PMC20.23s. When I swapped to a 272/250 I realised that the SU was somewhat slow and lardy. I now have a Nova and PMC 25.21is, which is much more sprightly and far better all round. It’s from memory of course, with a few years between the two systems. The Nova, with the right speakers, is very good, probably far better than it has any right to be for the money, in comparison with multi box systems. Maybe that’s all you actually need. It will be lots better than the SU, have all the current functionality, and is really simple. Some people seem to think it’s can’t be proper hifi because it doesn’t have lots of boxes and wires, and dismiss it as a ‘lifestyle’ product. But as you’ve already embraced the one box SU you are past that.
If you decide to go with an olive option and can find them, 72/HC/250 were a great combo, don’t take up a ton of space and sound better than the pre-DR and most of DR kit. Not sure what you’d put in front of it though and whether that would be a good marriage or not.
That’s probably a good place to start, they were great with the CDS2. Still, you’re probably better off sticking with modern kit unless you are just interested in the vintage stuff.
I auditioned the SU and the Nova with my Harbeth 30.1, and found the Nova too sharp and eventually exhausting. I like the SU better. Must say though that I have a relatively large room with little absorbtion, i.e. no carpets, curtains and the like.