I am looking to learn the setup for RAID on my OS (Pop OS Linux) and also backup my laptop.

I want a proper backup scheme in place on one external drive (drive A) and I want a RAID 1 setup between another external drive (drive B). Neither drive A nor B will mirror my hard drive, but I would like them to mirror one another for redundancy in backups. I tried setting up RAID 1 for them, but they sought to mirror my boot drive, which isn't what I seek.

Is RAID an appropriate tool for mirroring external drives in such a manner? Or is there a better tool? Do the drives have to be present at boot?

I hit a bump with needing the drives at all times when rebooting the computer without the drives present.