Hello
Welcome to the Board.
I withdrew from Xanax myself. Withdrawal from any benzo should be slow and gradual. It is not a drug to withdraw from cold turkey as that can easily cause seizures, especially if you have been on it for any length of time.
A general rule of thurab is to withdraw at 5%, making a cut every 10-14 days. Even at that, withdrawal can be tough. For me, the hardest was the great anxiety that happened with the cuts. However, it can obviously be done as I am clean of Xanax and have no cravings. It did take many months to accomplish, but slow and easy doesa it with benzo withdrawal.
If you are already taking Methadone, then yes, it wil probably help to some degree. I wouldn't recommend in any way at all starting up with an opiate to get rid of a benzo addiction. Truly, my best advice as someone who has been there is to see a doctor. That is m nuraber one, most heart felt advice.
Wishing you well
reach