I use some spare DSP33s with an old 518/562 combo as mixer/switch in a desktop system in my holiday home. (The 518 is the one Steve (syles) has a build thread on here where he converted it to accept a USB input.)

I’d imagine that a 562 on its own would work in the OP’s use case giving line in AD conversion as well as a variety of digital inputs feeding into a single digital line out to the speakers. It is high enough resolution for my rather basic recording to FLAC (vinyl to digital transcription) and work environment playback needs.