For headphones listening late at night I did just that… List of ingredients: (1) Raspberry 4 (2 GB RAM is enough, but the 4 GB version is not much more); (2) 16 GB Micro SD memory card for the operating system; (3) power supply for the RPi (I got a Canakit together with the on-off switch, what you need is 5V/3A); (4) case for the RPi. As the RPi4 can get warm and I didn’t want a fan, I got me a nice Flirc case which does a wonderful job of passive and silent cooling. (5) To stream with Roon I very much recommend using RoPieee as operating system. This is a minimal Linux distro with Roon Bridge built in. It is easily detected as endpoint by Roon and works great. Download the image file and burn it to the MicroSD memory card, e.g. using Etcher or similar software.
Time of assembly and installation - 10-15 minutes max.
Although it is recommended to connect Core and endpoints via Ethernet, my RPi is connected to my Wifi network without problems. I use this with a USB-connected DAC/Headphone amplifier, and love it for low cost, simplicity and very nice sound.