Conceptually I appreciate the language choices... but I found it distracting. I've never been a fan of subbed content and that's basically what this is.
To me this was a swing and a miss episode. I appreciate the attempt but this just fell flat for me.
Edit: I've learned there is an English version under the "Extras" tab. I'll rewatch later.
Edit 2: Watching the English version was MUCH better. After my first watch it seemed like our new character was being setup as a villain which, while interesting, didn't feel like the intention. Watching again I think she'll still have some learning to do, but not villainous.
The story itself was still pretty generic. Fine as a launching point for a new character, but I expect What If to get extra weird with things, and that was missing here. A sequel to this episode will be much better than this.