They make up for it in other ways. The only great attribute Lenglet has is his left peg. And that's a secondary attribute for a defender. I've seen him caught out positionally a few times last season. There's one goal in particular I'm thinking of but can't remember who it was against.
Lenglet would come with a reasonably big wage and is non-HG. He's a poor 4th choice for that reason.
I'd rather use Davies as an emergency left footed cb than bring Lenglet back.