HDD backup options for 8 TB computer

[cleric_warlock]

My main computer after some upgrades now has 8 TB of storage space split between 2 x 2 TB NVME SSDs and 1 x 4 TB NVME SSD. Due to drive speed, one of the 2 TB SSDs is my boot drive which is backed up to 1 TB by OneDrive which is where I keep all of my most important files/programs. I added the extra capacity because I'm expecting to need the space for data intensive cad projects and large video files and photo collections. I want a layer of protection for all this new capacity I have and having some extra redundancy for the data in my OneDrive backup definitely wouldn't hurt either. Setting up a NAS would be expensive overkill for my needs, so what I'm really looking for is an HDD of 8 TB capacity or larger that can receive backups pushed to it on a regular basis. In terms of capacity and especially reliability, what HDDs should I go for?

[goatedpenguin]

If your willing to give up like 4Tb which is a bit expensive or buy an extra 4Tb to run RAID 5 would be a good option. NASes are not that expensive these days, you can get a second hand cheap cpu + motherboard combo with 16gb of RAM, its not gonna cost for than 300-400 bucks. 

[Electronics Wizardy]

I'd just get a large external HDD here. Size don't really matter probably go for something like 16TB+ here.