If these two are going to act like children when they're supposed to be in their mid to late twenties mentally, I don't see the point of even making this an isekai. It's pointless and doesn't add anything to the story. Not just that, it actually drags the story down because the way that they act and think doesn't make sense.
We can see their thoughts and see when they communicate mentally. These are kids, they aren't adults in a child's body.
We can see their thoughts and see when they communicate mentally. These are kids, they aren't adults in a child's body.