Apple has several levels of audio to chose from:

Lossy AAC at 256Kbit

Lossless ALAC up to 24-bit/48 kHz

Hi-Res Lossless ALAC up to a maximum resolution of 24-bit/192 kHz.

They also have the spatial track options on a lot of music in Atmos, if that’s your thing.

All options are included with the base subscription, but listening to the Hi-Res audio typically requires an external DAC as well.