Also, what can I expect concerning RAID? That is definitely the most concerning thing for me, as I’ve never worked with it.

Generally speaking it’s recommended these days to use a software RAID rather than relying on hardware. If anything happens to that RAID controller you will need to replace it with a duplicate in order to mount your drives. Software RAID is controlled by the Linux OS and would be much easier to recover. There used to be a bit of a performance penalty for a software RAID but these days it’s negligible.