What is thick gum and how to get it? (Genshin Impact)

1) Primordial resin - restores itself in 21 hours
2) Weak resin - restores 60 Primordial resin, obtained for each level of the adventure rank at Katherine.
3) Thick resin - created on the alchemy table from 40 Primordial resin and 1 crystal core. The recipe can be obtained at the 3rd level of Li Yue's trust by completing weekly tasks. (After Adventure Rank 20, if I'm not mistaken)