I think it would be interesting to add this feature as a setting for those who are not keen on using "Keep Inventory" or Graves MODs.
Basically, the Utility Belt and Toolbelt could be protected from dropping the items equipped in them. And with Deep Pockets, as long as the player recovers their pants, the items stored in them would be safe. If the pants (with the obvious exception of netherite pants) with Deep Pockets were lost in lava, the items contained within would be lost as well.