This article explains how to hide or unhide backpacks in Knives Out. Including step-by-step instructions for enabling and disabling the visual display to reduce visual clutter.
How to Hide/Show Backpacks
How to Hide Backpacks

To hide your backpack, first pick one up on the battle map. With a backpack equipped, open your backpack, then tap the eye icon to toggle the backpack's visibility.
How to Show Backpacks

Same as hiding the backpack, after opening the backpack, tap the eye icon to toggle it.
Auto-Hides with Some Skins
Hidden with Set Skins or Collab Skins

With some set skins or collaboration skins, the backpack is hidden by default. Be aware that the backpack will not be displayed even if you try to show it in settings.
Items That Can Be Hidden
Helmets

Helmet visibility can be changed during a match. If you want to show your headgear, keep Prioritize Headgear Display checked.
Wings

Wing visibility can also be changed according to the situation. From the warehouse, you can select Display in Combat, Display on Sortie, Display in Lobby can be selected, so it's good to check the situations where you want to display your wings.