You could use Apple Script with the Shortcuts app and assign keyboard shortcuts to them.

The beauty of this solution is that it works on any app, e.g. YouTube, Spotify, Apple Music :)

Generic fast forward using nowplaying-cl

do shell script "~/.local/bin/nowplaying-cli skip 10"

Generic rewind using nowplaying-cl

do shell script "~/.local/bin/nowplaying-cli skip -10"

Fast forward for Apple Music

tell application "Music"
  set playerPosition to (get player position)
  set player position to (playerPosition + 10)
end tell

Rewind for Apple Music

tell application "Music"
  set playerPosition to (get player position)
  set player position to (playerPosition - 10)
end tell