I have Rotel RA-12 amplifier that has Bluetooth, Optical and Aux inputs. I’ve heard that Bluetooth compresses the stream to fit the data within its bandwidth. Does Apple TV do the same? In essence, what do I need to do in order to assure that the highest resolution streaming music reaches my amplifier? Thanks.
Roon does not support Bluetooth so this is not an option for a Roon user.
Apple TV does does not support hires files and converts cd files from 44.1 to 48 k. Not the best thing to do.
Suggest you look into a raspberry pi3 with a digi hat to send data to your optical input. A bit of searching on this forum will give you all you need to know about the pi3 and how to set it up.