I have a small apache case from harbor freight with a LePotato, mini router and a battery in it. I intended it to mainly be a road trip jellyfin/emby server (still deciding on which to fully implement) but I also have kiwix, Audiobookshelf and a simple nginx webpage to make getting to the services easier.
I’m also having a very similar issue. Desktop stopped working over Ethernet, cable works on another desktop as well as a laptop. It usually gets an ipv6 address, even though ipv6 is disabled at the router.
I had this issue with Comcast’s Xfinity and my solution was to clone the Mac address of a desktop on the Router.
I tried several desktops/laptops and several routers. All the desktops/laptops got just about full speed. All the routers where pinned at 93.78 or 31.23 for several tests. Cloning the Mac address on the routers that could let the router and devices connected get the full plan speed.
I’m running cat8 between my modem, router and main switch. The runs to the satellite mesh units are also cat8. I don’t want to ever pull wire to those spots again. I don’t regret it one bit. Everything else is cat6 with a couple 5e runs
I have a media server built in an Apache 1800 case with four 2tb 2.5" ssds in it.
If I where doing this, I would fill a hard case with nvme drives or 2.5" ssds and put 4k remuxes if you’re dead set on 4k, or 1080p remuxes, the ones on my server are 6-8 GB. Yes, you can get super high capacity ssds, but they are real expensive. The reason I have 2.5" drives in my box was price. I paid $50 for each one.