@mr_m. has heard the Atom driving $8 K speakers and it is up to the task....an astonishingly good product that will eat most of your budget, even IF you find one used. But try !!!!!!! Find a pair of ADS 710 or 810 on Craigslist and don’t worry about a sub. There are a lot of very high quality used vintage speakers out there that will sound great w 40 watts of NAIM power. Tannoy would be a real score!
The PowerNode is an amazing value and the application well developed. The amp section is NAD and IMO very nice for a switcher...well executed by a company with a lot of engineering talent, and ears..I drive a pair of Totems in a large sunroom and it also can rock. As mentioned it has a RCA sub output.
I would suggest a powernode paired with the PSB speakers/ sub engineered for it.
Have fun, go listen !!!!!!!