Best SQ Boost for Budget?...

I’m currently streaming non-subscription-based internet music and iTunes (CDs ripped as “48 something” AIFF from a Mac via an Apple AirPort Express over WiFi) into a PrimaLuna integrated amp and out to a pair of JBL L 65s.  Budget concerns won’t permit me to purchase a streamer and an outboard DAC simultaneously.  Would I get the most dramatic boost in sound quality by purchasing a DAC (looking at the Topping D90 or the Schiit Bifrost II) or via a BlueSound Node 2i?

Thanks in advance