I agree, except to say that it's possible to find a sub physician in the US who will prescribe both, it's rare in some areas, more common in others. I was on methadone for four years and now bupe for seven. I was never denied my 4-mg/day clonazepam. In fact it was prescribed by the second methadone clinic I went to in a major U.S. city.
Maybe I was fortunate, maybe I got " in" b/f these clinicians started to crack down on benzos in ORT.
I would call every bupe physician in your area and simply ask. Any that seem remotely willing, hit them up. I guess that's obvious, but when I moved once to a conservative town in Idaho that's what I did and I eventually found the one doc that would do it. Psychiatrists may be the best bet, that's what mine is at the moment. Helping me taper off benzos - at my request.
Best wishes.