Mod Loader: (Using)Fabric / Neo/Forge is fine to
Minecraft Version: Any/1.20.4 specifically
I was thinking it could be a new totem "Totem of Hoarding". You can choose how it looks and how to get them.
Basic functionality should keep your inventory and hotbar, with added config for keeping the other slots such as shield and armor.
(Optional) Making it compatible with modern trinket mods.
Thanks for your consideration.