Especially for hard drives. 8TB SAS drives are down to about $45 a piece.
Brand new enterprise-grade 8TB drives are more around $180 new. Meaning as long as you have redundancy (which you should anyway) then you can lose four used drives before it stops being worth it. Not to mention drives get cheaper so if your $45 drive dies 2 years from now you could probably replace it for $35 etc.
Arch and EndeavourOS are the same thing. There is no functional difference between using one or the other. They both use pacman and have the same repos.
Weird. I’ve had a Pi-Hole + Unbound running on a Pi Zero since 2018 and it’s never had any issues. I expected the Zero to kinda suck but it has been nothing but smooth sailing. It gets USB power from my router and even if my router reboots the Pi also auto reboots itself.
I do next to no maintenance on it and it just keeps on chugging along. Maybe once every six months or so I SSH in and do a pihole -up and that’s it.
Just buy them on eBay. Why does it matter where they come from? Again, four of them have to die before it’s no longer worth it. It’s extremely unlikely you’d be that unlucky.
Personally I have 15 drives in my NAS, all of them were bought used and they’ve been running 24/7 for 4+ years without issue. Originally I expected to lose at least one per year but they just keep chugging along. All of them have at least 40k power on hours, with the oldest 3TB ones having over 80k (9+ years)
I use unRAID so if/when one does die it’s as simple as pulling out the dead one, popping in a new one, and letting it rebuild itself.