Hi,
If you subscribe to Apple Music , some of your purchased music will be available to stream or download in Lossless or Hi-Res. Purchased music is 256 ACC kbps which has no DRM. Lossless music has DRM. Back up original tracks before subscribing. You will only have access to lossless versions as long as you have an active subscription. Original purchases will continue to be available for redownload as 256 Kbps after sub expires.
In Music app you will be able to select playback quality - High Quality (256), lossless or Hi-Res. If the purchased track has already been download, you can remove download and then either stream or download lossless version.
Jim