Might not be the answer you’re looking for, but Apple TV + Infuse is a fantastic media player. It has support for basically every codec so your server doesn’t have to be beefy — you can just direct stream everything. I stream full 4K UHD rips this way. And it supports Jellyfin, naturally.
No, unfortunately, it’s not a great player. Speed wise and aesthetically, yes, but codecs…
Blu-rays with Atmos use TrueHD Atmos, while streaming Atmos only supports Dolby Digital Atmos. Infuse does not support TrueHD Atmos, and there is no way to switch between the two, so giving up Atmos for the base 5.1 or 7.1 is your only option.
Similar case with Dolby Vision. Blu-rays use Profile 7, Apple TV only supports Profiles 5 and 8.4. So no actual Dolby Vision streams for you, just HDR10.