Intel NUC Roon Server is around $600.
A Raspberry Pi 4 with Ropiee is about $250 + linear power supply $90.
Roon lifetime subscription $830.
Spend the rest on a good DAC, amp, speakers, headphones if any of those items you already have are something you might consider upgrading.
I have the above setup in one system and I also have a Lumin U1 streamer in my main system. The upgrades to DAC amp and speakers are so much more bang for the buck then the small improvement in sound by spending $5k more on U1 streamer...don’t get me wrong it is a great streamer but it was the last component I upgraded. I was shocked and surprised at how good the Raspberry Pi sounds into a good DAC (USB connection - no hat). Everything I read and see online says buy a streamer costing thousands.