Volume Boost feature

[qwerty12]

I know of two Android clients (third-party/ish) where you can do this:

• Kodi with a Jellyfin plugin installed - you can adjust "volume amplification" or, rather, the volume of the center channel for multichannel audio.
  That said, Kodi is best suited for use with Android TV. It's usable, but not comfortably so, on an Android tablet. It's downright pointless to install on an Android phone.
  
• Findroid if configured to use mpv from its settings to playback files. But setting up mpv's volume boost isn't very simple. Findroid exposes the mpv.conf; you can edit it and add something like volume-gain=8 (and volume-gain-max if needed) to the file. But Android being what it is, you'll need to set up ADB and edit the file from your computer, or set up something like wireless debugging, Shizuku and MiXplorer.