"Be that as it may" means "it doesn't matter" (or, as young people say today, "whatever!"). The "in" at the end of the sentence is technically incorrect, since we try not to end sentences with prepositions. That is why we use "in which" in the middle of the sentence: it avoids putting "in" at the end. Having "in" twice in the same sentence is the mistake, because you need to choose either "in which" or "interested in" (you can't have both).

"Be that as it may"; used to mean that you accept that a piece of information is true but it does not change your opinion of the subject you are discussing.