Hey there! Sorry, but the Aetherproof resin recipe is in the "Simple" category and requires you to be lv. 21 so you might need to grind a little further 😅. Have you tried completing the levequests at one of the inns? They can help you level-up faster, especially if you have lots of items on you.
With that being said, yes I agree I need to rebalance the grinding post lv 30 as it gets a lot slower and we're starting to have quite a few jobs lol.
For the Wyvern and other enemies/items, for now there the 0.4 Item Location Guide PDF you can get from this Itch page that mentions where to find some of the enemies (Wyverns are in the Churning Mists, which you access from Dravanian Forelands), but adding a Bestiary is something I plan to do in a later update as well.