Hi Gianfri,
I’m using DIY Raspberry Pi dac/streamers for multi-room distribution. Essentially these are Raspberry Pi computers with a DAC hat attached running a special Roon Linux based software. Personally, the DAC hats I’m using are from a company IQAudIO but there are a number of others. Here is a pretty good article on one of the newer companies, https://darko.audio/2019/12/a-streaming-dac-with-cover-art-display-for-us154/. Currently I think most folks doing this are using RoPieee to get Roon onto their Raspberry Pi, here’s a link on doing that, RoPieee Beginner's Guide. I setup mine before RoPieee was around so I can’t help you much with that part of it.
If you don’t need the DAC function it should be even easier to set up some Raspberry Pi’s as streamers, though you may want something to clean up the usb output. I believe the company ALLO has a hat for that.
For a bit more cost you could also look at something like the Sonore rendu’s, https://www.sonore.us/. These are purpose built streaming computers that are pretty much plug & play. You do however need a separate DAC.
Regards,
Mario