All in all, the Uniti Star seems the perfect choice for you and your speakers: simple, versatile, powerful and good.
If you want to use a turntable, just purchase a good phono-pre suc as Rega, Trichord ecc…
Quite another thing if instead you want to set up a system with separate components with more pieces, more cables, more costs …
There’s certainly SQ improvement with Naim separates, but Uniti Star is a one-box solution, so it also depends on how big a footprint you like your kit to have. I myself am a very happy Star owner, paired with small Dyns because of the super small listening room. It also depends what your previous amp was. For me the upgrade was so big that after one year I am still so struck with amazement that I am not longing for something else.