In my opinion, taking Xanax for 20 years is much too long since Xanax is intended for short term anxiety or panic attack and not a maintenance type drug for general anxiety disorder. See your doctor for advice on gradually cutting back on Xanax and something more appropriate such as a daily generic version of Lexapro.
You could try switching to some natural alternative such as valeriana wallichii commonly called as Tagara. However, don't mix the two things. And it is better to taper down your doses instead of increasing them.
20 years is some two decades. Xanax is one of tricky medicines I have encountered. I think dependence is usually deep. More psychological or more chemical, IDK. That is the tricky part too. But not stronger than our ability to control and take charge. It may get difficult but it takes time to be independent again. Anyways how much quantity of xanax do you use?