To add to your decision paralysis, a USB 6 bay DAS is cheap and power efficient solution.
Personally, I have a SSD with a 4-3-1 backup for important files and a 16 TB hdd with a 2-2-0 backup for unimportant files.
Regardless of what you go with, I'd recommend buying less quantity of higher capacity drives (14+ TB) instead of more smaller capacity drives. I'd also make sure you have a backup strategy in place first, and then worry about RAID.
Do you have any recommended tools or ways to set that up?