Forget tubes at this price level and forego the center speaker, which will allow you to use a stereo amp and put more $ toward better L/R speakers. Plus, listening in the nearfield you’ll unlikely need a center speaker anyway. I’d get a PS Audio Sprout100, which takes care of your amp and DAC, and a pair of Silverline Minuets. Used you’ll be under $1000 and new $1300 and then just add a sub later when funds permit — for your application I’d get an SVS SB1000 that’s $500 new. This will give you a legit full-range 2.1 system that sounds amazing, and if you upgrade the amp/DAC later (tubes or otherwise) it’ll get even better.
If this is still too too pricey you could go with Wharfedale 11.1 Diamond speakers for $300 (on sale at Music Direct) and it’d still sound pretty damn good. Hope this helps, and best of luck.