Raid can protect you from a single drive failure in case you need an “always on” setup. Even then, if the drives are identical, they can fail within days from each other. If you don’t have monitoring, you’ll lose everything before you can react. I feel that’s not your use case.
You need backup. You can use something like rsync or even better borg backup. Keep the backup offline and backup often. You’ll be safer that way.
You can backup to an external USB drive (that’s what I do), or setup a small backup server (with RAID if you want).
If you use Borg it will do the right thing out of the box with minimal configuration - compression, deduplication, encryption, and incremental backups.
The first backup will be full and take longer, but subsequent backups will only target changes and will be quite fast.
Restoring is very straightforward, even if you only need a single file you deleted accidentally.