I think there should be a simplified crafting system when it comes to resources. The base materials should be called Wood, Ore, Herb, Monster Trophy. And these would come in Tiers e.g Tier I to Tier X. Each zone would have resources of different tiers. End game zones would have tier X resources. 'Monster Trophy' would be a generic material looted from monsters and gathered from monster corpses. Max level monsters dropping Tier IX, and Bosses dropping Tier X.
When it comes to equippable items, players should be able to craft end-game entry level gear. Let's say that max item level is 100. Max level quests rewarding item lvl 50 items, and crafted gear being between item level 1 to 70. Perhaps some gear slots e.g finger, gloves and footwear could be crafted at item lvl of up to 70 and upgraded to max item level. But all other slots would need to be obtained by doing other end-game content.
Recipes could be something like:
Evergreen Wood Bow (ilvl 10) - x1 Evergreen Wood Bow (ilvl 5), x100 Wood Tier II, x30 Ore Tier II, x50 Herb Tier II, x100 Monster Trophy Tier II
Each item could exist on every item level starting at Item Level 5, then increasing by 5 levels 10, 15, 20, 25, etc. The recipe would be the same amount-wise, just the higher tier resources need + the same item of the lower tier. This way all resources of all tiers would be relevant all the time because if you want to craft item lvl 70 armor, you first need to buy or craft the same item on item lvl 65. This way even new players at level 1 could gather Tier I resources and sell them to high level players or craft low level items and sell those so higher level players can buy them and upgrade.
This would be a straightforward way of implementing the resources. Player wouldn't have to worry about finding out what monster or interactable tree drops certain item. They would only need to check which zone is for example Tier VIII zone. Once they go there, every resource gathered there would be of Tier VIII, and every monster killed would also drop 'Monster Trophy Tier VIII'.