You can pick any hard drive, preferably a NAS/Server Oriented one.
They do have to match if you’re doing a multi drive RAID/ZFS though.
It’s kind of complicated, if you can afford the lifetime price, HexOS has some amazing things going for it as a fork of TrueNAS, but TrueNAS is FOSS and has probably everything you need, if you’re planning on doing Jellyfin, you might wanna stick with TrueNAS Scale.
I presume you acknowledge the risk imposed going through the Custom NAS Route yes?
Yes, although the setup was really what took the most time (especially the VPN setup), but I always go through all the settings of each device/app I own.
Maintenance only takes me 5 minutes per week as it’s mostly automated. I presume similar options are available on TRUENAS.
I don’t really do any hardcore self-hosting, but I have an absolute dinosaur of a 13 year old machine that’s currently running things like Joplin, Jellyfin, Fresh RSS, Immich and it all works flawlessly.
I think when I was looking into hardware that would be optimal for a NAS build, there was a key difference in the hard drive types one must select for what is, naturally, a write-heavy environment and application. I found that it’s generally not recommended to use SMR drives, as their overlapping data tracks create a huge performance penalty for write-heavy operations. Not only that, but when used in a RAID array, can also, generally speaking, increase the risk for drive failure when doing heavy array integration[1]. I’m not a storage media expert, but these are the most common points I’ve found across various articles.