How to fix this crack in the shower wall?

https://mander.xyz/post/46896321

How to fix this crack in the shower wall? - Mander

We recently moved into this place and the shower has this crack in the tiles. I imagine this is quite bad in terms of humidity creeping into the wall? Is there a way to fix this without having to redo the entire wall? Thanks for thinking along! [https://mander.xyz/pictrs/image/3cbb484d-4fc1-495c-a3be-fbc62bb5731d.jpeg]

Coworker of mine had a plumber drill a hole in the wrong place, so now he had a tile with a hole in it. Plumber got someone in to fix it with colored epoxy. Says he can't see where the hole was.