The drives you’re seeing with the “too good to be true” pricing are what most people call “white label” drives. From what I understand, it’s either refurbished or something that didn’t pass the big-brand QC so they don’t get the brand name. Slap a white label on it and ship it.
WD, Seagate, Toshiba will all have approximate price parity through various levels of HDDs. You can base your shopping on these prices for first quality drives. I like WD. Currently I’m running zfs raidz2 (one parity drive) on four drives. Two are WD, one Seagate, one Toshiba. No problems yet but this array has only been on for 9 months. Prior to that I had a 2-disk striped raid with 2x 4tb WD blue drives and it ran for 8 years without an error.
Usenet is still a thing and us binary kids have completely RUINED it. the *arr stack plays well with Usenet. TrueNAS Scale is Debian based and has apps and containers. Plex, Jellyfin, *arr, qbittorrent, SAB newsreader. It wasn’t trivial to learn to set up but mine is automagic now. VPN is cheap now and lets you get on the public trackers but private trackers are where it’s at for stuff too old for Usenet
Or OpenWRT on a thrift store Linksys