"Lost" Apple Lossless?

I's an Apple + subscriber and have enjoyed re-downloading Apple lossless versions of many of the songs on my iMacs, iPhone, etc.

Recently, on one of my iMacs I inadvertently converted hundreds of songs to Apple Music ACC audio files, which rendered the files in a smaller, but less enjoyable format.

I want the Apple lossless files back, but when I select one and try to convert it, I get a message saying tat the song "could not be converted because protected files cannot be converted to other formats."

I can re-down load the songs, but there are 800+ on the playlist I'm most interested in.

So, can I "remove download" or otherwise delete the smaller files, then re-download the playlist from the cloud to re-gain those lossless files?

Thanks for any advice.

PS - the song files from the same playlist on my other devices have retained their lossless format.