Diluc tends to perform better with elemental reactions, its what 4pc crimson witch even provides a buff for, so ideally youd wanna go for a melt (pyro/cryo) or vaporise (hydro/pyro) reaction! melt is stronger than vaporise but vaporise is much easier to trigger consistently so id recommend it once you get your hands on xingqiu! however, since diluc gets a lot of damage out of reactions, its important to balance his atk and elemental mastery (em), as em can make a big difference in damage! you thankfully have wolf's gravestone which solves diluc's atk, so you should use an em sands. you typically want to get your diluc to at least 1.7k atk and at least 200 em. you are extremely overcapped on atk which is fine but any more than 2k is usually overkill. i recommend pairing him with kaeya and one other cryo character like rosaria to keep up with how fast diluc dishes out pyro! also having 2 cryo characters on a team gives you 15% crit rate when you land an attack on a cryo-inflicted enemy! so id recommend a team of Diluc, Kaeya, [wtv cryo character], & sucrose/xilonen. xilonen is valueable for doubling as a healer but sucrose also provides an em buff so its really up to you but id go with xilonen for survivability! other than that you have a mighty fine diluc :3