A lot to unpack here. For example, do you want to have your CD collection on a NAS connected to your network, with separate streamer and DAC? Or do you want to have an all-in-one solution; these tend to be pricey, however, and then you’re stuck with their choice of DAC forever.
Do you want to separate the software side of the equation by running Roon on your server? That’s what I do. If you’re interested in Roon, but want to get some experience of its efficacy (vs.Bluesound for example), you could load it up on your computer for a free trial and use its software while using the bluesound hardware as your streamer/dac; bluesound is roon ready. If you like it, you can then focus your attention on the streamer and dac choices without paying up for somebody else’s proprietary software (e.g., Aurender, Innuos, etc.).
But $18k for your digital side is a hefty budget - in my experience, you can get closer to SOTA performance for less $ on digital vs analog. Regardless, there are some on this forum whose beliefs/experiences suggest that you need to spend a material portion of your budget - relative to the DAC - on the streamer; you’ve already heard from several of them. There are others, like me, whose beliefs/experiences suggest that if you spend more than a relatively small amount of $ (i.e., <$2,000) on a streamer, you may be spending your money on features that have little to do with sound quality. And I agree with @deep_333 re reclocking as unnecessary (unless your streamer and dac combo has a jitter problem, which is highly unlikely anywhere near your budget).
Bottom line: IMHO, the DAC is far and away your most important decision. At your budget, I’d listen to as many choices as I could in a relatively controlled environment. Only then would I worry about server/streamer options.