His average kda is literally the worst ive seen on any champs release.
People said similar things about Orianna, Jayce, Elise, Lucian, and Lee Sin when those champions came out.
Lucian in particularly was widely regarded as awful and out-classed by all other marksman by the community for at least a month after his release.
Generally speaking LoL King shows newly released champions within the 3 worst win-rates for a solid month after their release as well. Diana and Zyra are the last champions I remember that shot up to ~55% upon their release, otherwise even release Lucian and Elise, stronger than they are now, where not doing to hot.
Champions in LoL generally take a long time to master, especially when you consider Elo isn't based on the champion you pick, but your account overall. Mastering champions is only about ~5% knowing what their kit does - the other 95% is knowing exactly how that measures up against a wide range of opponents, what time periods you can push your kit to the max, what times you're at a disadvantage, what champions you can overwhelm, what champions will overwhelm you.