UPDATE: This is now working again see the article here: https://www.steamdeckgaming.net/post/genshin-impact-3-6-is-working-again-on-steam-deck
Unfortunately, as we feared, the Genshin Impact 3.6 Update has stopped the game from launching on Steam Deck.
After manually re-installing the launcher to double-check, the game no longer loads and sits on a black screen, no error is shown now.
We have updated our original article here to reflect this.
The community is also reporting similar results, we will keep testing updated and any workarounds that come into play, if you know the other method that allowed you to play previously, that is being updated and should work again shortly.
We will continue to monitor the updates and feedback, once we have news we will announce it again.