Maybe it's time to ban all games with "loot boxes". For serious, real.
Instead of a loot box, have a slider with all possibilities that you could get out of it, and manually be able to select the item. Whether or not you actually get the item, would still be a percentage, you won't get your desired item every time. But it would take the "chance" out of what you're actually getting, the uncertainty, and hopefully, much of the dopamine hit.
Maybe even the percentage chance of getting the "selector box item", would increase a few points every time that you get to that point in the game (defeat boss, etc.), such that eventually, after enough play-time, you are basically guaranteed to get the item. Consider the behavior re-enforcement, "practice makes perfect", and "a penny saved, is a penny earned" (percentage point).
Edit: So as not to ruin gameplay, and allow a Lvl. 1 character access to Lvl. 99 weapons and armor, you could limit the selection range of items by character level, that would be fully acceptable.