TLDR
genshinimpact is NOT official, and is currently dead.
genshin_impact is alive and well, go there instead.

@[email protected] already got an answer on genshin_impact, but for anyone just wandering in, here is a rundown.

genshin_impact was created by @[email protected], who also created [email protected]. Arorus has posted to and responded in both of their communities, and looks to be trying to grow both. They wrote their own community descriptions as well, simple though they may be. Looks good!

genshinimpact was created by @[email protected], who also created 30+ other communities. Chilio95 has not posted to or responded to a single community of the 30+ they have created. They chose to use the name the unofficial subreddit uses, “r/genshinimpact,” but copy and pasted the sidebar from the official subreddit instead. A weird choice with that “official community” text, especially given Arorus’ genshin_impact already existed. Reddit API is still available, so I gave it a quick glance and I couldn’t even find them posting in most of the Reddit sub equivalents of communities they created here. They also tried running a scheme on Reddit where they would charge to upscale people’s photos using AI, make of that what you will.

I’m not saying Chilio95 is squatting local communities so they can have ownership of them without putting actual effort into building said communities, but it kinda looks that way and I hope it isn’t true.