@mitch2 the best streamer you can hear today is the Taiko Extreme, soon to be outclassed by the latest offerings. This is out of my price range and your stated range. What they have done to build this "streamer" should be the foundation of what you’re looking for. Power is the number one consideration. I won’t go into the other factors too much.
I’ve been building my own music servers for many years, having followed discoveries that have led to what Taiko is doing. I’ve built my own server as close to the Extreme as possible as well as built similar sounding servers. Each server or streamer will have its own sound profile. What I have targeted is what many look for; clarity with a black background, an expansive but accurate sounds stage and as close to a real life or analog listening experience as possible. There are other characteristics but these I’ve found are critical. The main goal is to reduce noise introduced by components.
In your search, if able, evaluate power and timing attention in the forms of latency and other digital impacts like jitter. The other critical factor I’ve found is upsampling ability. Upsampling in addition to being able to play high resolution sources is a significant factor in sound quality. My DAC can process DSD1024 native and PCM 1.536MHz so I upsample to those frequencies and I absolutely hear a difference. My DAC has NOS capability so I do that from my server/streamer. This means I have better control over the variety of available filters.