It would actually be a really good idea for you to get on buprenorphine. Whether it is just for the acute detox or for an extended taper of six months, it won’t be nearly as difficult to get off as where you’re at with methadone right now. It won’t provide the same relief from cravings methadone does, so that is something you’d maybe benefit with an extended treatment program with.
Nowadays they recommend people getting off methadone do an extended taper on buprenorphine. That is what the science now suggests at least. I wasn’t comfortable using buprenorphine for more than the acute withdrawal, but I also tapered methadone down to a low dose over almost two years before getting off. You won’t have had that experience, so an extended taper off buprenorphine is a good idea to at least consider. And, again, getting off that won’t be as difficult as you might think.
I don’t generally like the idea of long term inpatient rehab, as opposed to inpatient followed by an extensive IOP, but that’s really up to you. Long term rehab program are very difficult, and generally don’t do enough on their own when it comes to re-entry/aftercare. In fact they are notoriously unequaled for that stuff, which is why continued IOP support is so useful.