IDEAS FOR RYZOM

Remove unnecessary weight and volume in the character's bag. Ideally, move them to a separate invenatr tab so that they don't get mixed in with regular (non-quest) items.

If the quest requires resources or items that can be used in other ways (not only for the current quest), then move them to the quest section and fix them as the goal of the quest, that is, block other uses, remove weight and volume.
This is especially true for auto-launcher gear, the quest for which now requires you to strip down and put a mount next to you so there's somewhere to put the overly heavy items needed for the quest.

There could be an exploit to cancel a quest to quickly transfer a bunch of stuff without restrictions. In that case, I suggest just removing the items marked for that canceled quest. Or do not bother registering them in the inventory at all, and just add a number to the quest counter and, as a consequence, eliminate machinations at the root.
I got around the problem with a lot of quest resources in the Raizome prototype by reducing their addition/removal to a number in the quest window. It doesn't matter to the player what exactly he collects - spider's web, fallen leaves, or guu curse - if only quest progress is important and these things can't affect anything else :)
As a small consequence of this, all quest items are actually considered to be one type of raw material (only the picture differs, the type of which is determined by the quest). And the window of mining skills is not clogged by a mass of highly specialized skills of search and mining of purely quest items, not interesting outside of specific quests.