I believe you can get this if you setup the underlying disks with dm-integrity, though I’m not sure it’s really worth it since it’s a very manual setup and has lots of potential edge cases and performance issues. Basically when the underlying disks are setup with dm-integrity, each read is verified with a checksum, if the checksum doesn’t match, the dm-integrity layer will return a read error and mdadm will log an error and automatically fallback to the secondary mirror. A “scrub” in this case would simply be reading the disk to /dev/null with dd, then checking the mdadm logs for any errors.
Note that it’s been a long time since I’ve messed with this, so it’s possible I got the exact details of the setup wrong.
I can’t access this site since it seems to require an account, but for DASH streams the playlist URL typically ends in “.mpd”. yt-dlp can download DASH playlists if you give it the URL. That being said, this seems like some kind of official TV streaming site, so it almost certainly also has DRM on all the video content, so there’s likely no simple way to just download it.