There’s not any anime, but there’s a official comics here: https://manga.honkaiimpact3.com/book

The game is on pc as well (windows only :( ) and it’s worth until ~chapter 23 where it changes course and may either be epic or the worse ending in histories of ending depending on who you ask

And yes, gacha game that matters until chapter 11 where it stops using the characters you build and just gives you the character to play the stage.

There’s a stamina system so you cannot bomb rush the story, but it’s not that restrictive. Of course the game will shower you in in-game currency at the start, so it may be easy to get the latest universe ending god and clap everything due to severe powercreep.

Please note that it’s nothing like Genshin impact or Honkai: star rail. So if you have gripes with those game, don’t expect the same here. (Genshin influenced Star rail and ZZZ, but honkai only started to get influenced by chapter 23)

If you’re still not sure, there’s cutscenes/songs on the official game channel to get a taste (might spoil you)