And what would those “multiple reasons” be? Where is OP storing 400TB worth of downloads?

Yeah it only comes with 6 trays, so you’ll need to order more, but you can fill out the entire front section with drives.

I’m currently at 3TB a month and that’s with capping my seeding speeds to 2Mbps and remote streams to 3Mbps (essentially SD quality) to conserve what little upload speed I have to split amongst my users.

I don’t know why you’re so adamant that this can’t be the cause when video is hands down the most common reason for high data usage. Downloading a video is just 1x the file size in data usage but streaming to friends and family can easily increase that 1x infinitely based on the number of users. Then throw seeding on top of that and you increase it another 5x or what have you.

I’m browsing Tautulli right now and the little 4k content I have has a bitrate of 25Mbps for an hour long TV episode while movies like Akira in 4k has a bitrate of 90Mbps, Bladerunner 2049 70Mbps, Encanto 72Mbps. That crap adds up quickly. Imagine 6 kids who all have Encanto playing over and over again in the background, which amounts to 1TB of data used in 6 hours if they all play it 3 times.

What do you suspect is the cause of so much data usage if not video streaming?

I use a Fractal Design Define R6 but their newer model is around the same price (it actually appears to be $60 cheaper than the Silverstone case on NewEgg) and can hold the same number of drives. They’re solid cases.

https://www.fractal-design.com/products/cases/define/define-7/

For your lack of SATA ports, you can either buy a new mobo (use PCPartPicker and filter by SATA ports) or an LSI SAS HBA card to gain additional SATA ports.

Plenty of 4k HDR videos are 50+GB each and OP could have a dozen people or more watching each day plus new downloads, online backups, seeding, etc.

I have a decent sized server with terrible upload speeds in the 15Mbps range that I share with some friends and family, and I still have 5-6 people streaming from my server almost constantly. If I had a symmetrical connection, I wouldn’t be shy about sharing it more and uncapping the remote bitrate settings and I could easily see myself hitting these numbers even though almost all my content is 720p and 1080p.

Tony Stark is always prepared.

Video is what gobbles up that much data. They likely have friends and family streaming from their media server.

I use Ersatz like others mentioned and it works fine, though I don’t fully understand how everything works. Following a guide was enough to get several channels setup, but since I also have an antenna and HDHomerun set up, I had to also use xTeve to combine the real and fake programming guides.

This works as expected in Emby (which means it probably also works in Jellyfin), but in Plex it breaks the guide as the channels get all mixed up with respect to their programming data meaning I never know what I’m going to be watching when I click on it. If you don’t have an antenna set up already, this probably won’t be an issue for you.

I can’t give you much technical help, but I’m fairly certain that if you’re seeing washed out colors on an HDR rip, it means Plex isn’t actually playing in HDR and is instead transcoding it down to SDR as this is (or at least used to be) a common issue with it.

If you check the administrator tab in a browser to see the playback information for the stream (or with something external.like Tautulli), does it show that the file is being direct played? That’s where I’d start. It could be something with the file, subtitle usage, Plex itself, the client you’re using it watch the file, or a network issue that’s causing the problem. I used to ignore HDR content entirely as I had similar issues, but with the TCL and LG TVs we have now, both using Roku, HDR content plays (locally) without issue. Remote play doesn’t work but that’s because we have atrocious upload speeds with Comcast.