If you bought the Atom from a reputable dealer, you should be able to tell them you are looking for an upgrade, state your budget, and they should be able to demonstrate a few things, one of which will knock your socks off.
I don’t think we can do that as effectively on the forum.
That’s an interesting question because I’ve started to think differently about my Atom.
I initially got it just as a toe in the water for streaming (and being self-contained could be repurposed later) since I’m primarily a CD and FM or vinyl dinosaur.
Consequently my Atom operates as a source through an active pre/power set up with SBLs supported by a sub, so a true ‘mullet’ from its perspective, and I’m increasingly amazed how good it is at the things you describe, depending on the quality of the recording it’s retrieving.
The Atom itself does have a pre out connection, which suggests a good degree of confidence from naim as to what they created. If you can, I’d be tempted to try it with a different amp/speaker combination and then you’ll know.
For my part, I’m beginning to think I’ll try that too, just to see.
Nova is an obvious solution but considerably better still ND5, or better still NDX2/SN3. If you wanted future upgrade flexibility then 282/200 preferably a DR200 which will be even better at powering the 282.
A good suggestion, except that… it won’t drive anything without a power amp between it and the speakers. Also, the A6 lacks a trigger out, so for those reasons I would suggest the EverSolo A8, which has the trigger out, and a somewhat improved DAC. Although whether the difference is actually audible is doubtful.