Looking for best streamer without DAC under $3500

$4k for a computer? The only reason why somebody would do this IMO is because they are stuck using usb and they need to get the best performance possible out of a flawed interface. SSD for music, also overkill. Again, the only reason for using ssd is because you need to place a server in your audio room and you need to have the system as quiet as possible. Save the $4k, get a 5-8 year old Mac with an internal 500GB ssd to run roon, get a good couple of TB drives to store music on and for backup (or create your own raid 1), and place in t anywhere in your house except the audio room. Then go get a great dac That has an Ethernet connection and you will be in good shape.
If you buy any proprietary server, who is going to support this? If you buy an Apple, thousands of Apple geniuses in person or on the phone can help. If you buy a proprietary server which probably runs some kind of Linux OS, how are you going to backup the attached disks, and worse, how are you going to restore your ripped data if a disk crashes (ssd or hdd disk will crash).
There are quite a few people that promote this on different sites

If you can find one, a used Innous Zenith MKII would work just fine, and it can host Roon Core.  

What???? Oh boy don't agree but to each their own. I used a Mac a while and thought it was pretty good until I tried some other options. The computer's background processes create a ton of noise and so do the power supplies which feed back into your electrical grid. Why does Taiko Extreme sell like hotcakes for $20,000 or the Innuous Statement for $15k? Because they sound better. To OP: Lumin U1 Mini. Love mine! Versatile and quiet which is way better than the Mac I used to use - its more settled and quiet. More of a high end source than a computer.

Well folks, I have my two cents, considering the 2 million cents already expended on this thread, wash your hands and good night ! 

Owl-did you read the review of the innuous in last months TAS? It wasn’t that great, it came across as a work in progress review.
when was the last time you auditioned a Mac mini using Ethernet to a great dac? Probably never. Like I mentioned earlier, most of the people doing $5k-$15k servers are hooking them up To a dac using usb and trying to get usb to sound good. Also, these same people are putting these servers in their audio room so they have to perform tricks to keep everything silent.