I don’t understand why everybody is fanatic about RAID in home environment… Until you don’t have a bulletproof backup, you shouldn’t even think about it

dedicated software that can create verifiable historical backup files. Like Veeam or Macrium, or the new generation like Duplicacy, Arq, Borg, etc. All of them have integrity verification integrated.

if you use real backups, and not just simple copies, then your backup software has verify function. For simple copies you should use hash files or something that can build a hash database and verify it. Btw. you should already use hash checking for live data anyway. For archiving you can create winrar archives with 10% recovery record, so it can self-verify and self-repair easily.