For the Steam library I suppose?
I meant RAM deduplication. https://duckduckgo.com/?q=linux+same+page+merging&t=fpas&ia=web
For on disk deduplication, Steam supports user-specified locations for installing games and dependencies like Steam Linux Runtime. 2 users can theoretically use the same Steam library at the same time. To evade issues, auto updates should be disabled in the Steam clients. Steam doesn’t support completely disabling updates afaik, the best is setting update period to 3.00-4.00 AM. DXVK cache files must be located outside the Steam library folder. Otherwise if 2 people play the same game with Proton at the same time, cache files may be corrupted. (the default is the folder with game exe) Info on changing cache file location: link
Do you mean a video with multiple songs split by chapters? Like this one? You can use yt-dlp with --split chapters -x
options. -x extracts audio.
Kodi + PVR IPTV addon. I use this addon, keep in mind that it doesn’t support Apple silicon https://kodi.tv/addons/matrix/pvr.iptvsimple/
I install KDE Plasma on laptops I intend to use as a server. If the PC is easily reachable you can use the GUI to quickly manage files or use the terminal. Disable search indexing if you install GNOME or Plasma. I never used Debian but I assume the base system is as clean as it can be.