I don’t know how waterproofing gets done where you live, but if a customer here in Finland asked me about this, I’d just tell them it’s mostly a cosmetic issue - and trying to fix it risks puncturing the waterproofing membrane behind the tiles.

You’re also highly unlikely to find a matching replacement tile unless whoever did the bathroom stashed the spares in the attic or something.

Anyway, the point is this probably isn’t going to cause water damage down the line - what actually keeps the walls watertight is behind the tiles, not the tiles themselves.