I’ve thought of a solution to this, for any folks transitioning over and looking to use Galley view without seeing every instrument for every player, and without having to toggle filters to see the active instrument for each player at any moment of the score.
Create a duplicate score layout called Wide Score, or Galley Score, whatever you want. In Page Setup, change the width of the page to something wild like 8000mm. In Staves and Systems – Casting Off, disable “fixed number of systems per bar” if it’s active. Voila. Galley view, with no extra instruments and more page-view-accurate vertical spacing. I may start using this myself.