If you're relying on one hard drive not failing to preserve your data you are doing it wrong from the jump. I've got about a dozen hard drives in play from seagate and WD at any given time (mostly seagate because they're cheaper and I don't need speed either) and haven't had a failure yet. Backblaze used to publish stats about the hard drives they use, not sure if they still do but that would give you some data to go off. Seagate did put out some duds a while back but other models are fine.

Hard drives aren't great for archival in general, but any modern drive should work. Grab multiple brands and make at least two copies. Look for sales. Externals regularly go below $15/tb these days.

My WD Red Pros have almost all lasted me 7+ years but the best thing (and probably cheapest nowadays) is a proper 3-2-1 backup plan.

I think refurbished enterprise drives usually have a lot of extra protection hardware that helps them last a very long time. Seagate advertises a mean time to failure on their exos drives of ~200 years with a moderate level of usage. I feel like it would almost always be a better choice to get more refurbished enterprise drives than fewer new consumer drives.

I personally found an 8tb exos on serverpartdeals for ~$100 which seems to be in very good condition after checking the SMART monitoring. I'm just using it as a backup so there isn't any data on it that isn't also somewhere else, so I didn't bother with redundancy.

I'm not an expert, but this is just from the research I did before buying that backup drive.