I have a pair of powered Mackie monitors that I’d like to use in a room in my house, connected to some kind of Roon Endpoint that I’ll use the volume control in Roon to turn up and down.
My Mackies have a choice of 1/4 TRS in, XLR in, or RCA in.
Our go-to is the Bowers and Wilkins Formation Audio, but that depends on your definition of ‘cheap’. Retails at £599, and the quality is sublime. It is built for wireless connectivity with RCA outputs.
Bluesound Node 2i springs to mind, wireless , line outs, fully Room Ready and has support for other services Roon doesn’t and it’s not hugely expensive. DiY options using a Raspberrypi are much cheaper and you can choose a variety of output boards.
MobileFun.co.uk seems to have a good supply of Audio Chromecast and I found them good to deal with. Other than being a satisfied customer I have no connection to the company. (Just a note: the units ship with UK mains plugs, so you if you are outside the UK you will have to supply your own.)
I have no dealings with Lumin unfortunately, but they are at relatively different price points. The Formation Audio is more of a multiroom/lifestyle product much like the Bluesound product range, opposed to HiFi streamers like Lumin/Linn/Naim et al. I have very little doubt that Lumin would perform at a much greater quality than the Formation Suite but cannot comment on the robustness of Lumin without trying it for a couple of weeks. Ditto on the Bluesound reliability, I frequently had dropouts and serious bugs when I had dealt with them in the past, but always sounded exceptional at the price point (when it worked 95% of the time!)
My Bluesound Node 2i has been reliable.
Some users have reported sync issues across zones. I’ve had them in the past, but not lately. Be sure to keep the firmware and the application software up-to-date.