Many thanks for supporting my work and providing the screenshots with your question!
The first screenshot shows that the files in question are all M4P files (I've adjusted the topic title accordingly). M4P is Apple's DRM-protected version of MP4/M4A which is not unfortunately supported by Mp3tag.
There was a time where you could exchange the DRM'ed files with "free" files I think via iTunes Match, but I don't know how this is working now with Apple Music. There are lots of third-party tools that claim to remove the DRM, but I guess most of them simply re-encode the file which is a lossy process.