I don't believe you can equate adderall to methadone or bupe. Methamphetamine addiction is very different from opioid addiction, I believe it's a red herring to think that because maintenance/substitution works for one addiction, that it'll automatically transfer to another type of addiction.
It depends what your goals are - but it's is my belief that if you aim to quit, substitution with prescribed amphetamines has little value. If not, I also think that switching to them over meth has limited value in terms of being 'healthier'. There's an argument to be made that being prescribed a legal alternative reduces many of the harms that are associated with drugs simply because they're illegal - price, legal worries and so on - but as a prior meth addict, at least IMO, I find the idea of 'substitution' for meth completely inapplicable. Unlike opioids, whereas I find even a small amount, not enough to get me high, will provide relief if I'm in wd, I found the opposite with meth - using a little bit kicked the cravings into overdrive and set my mind on one task only - get more. Furthermore, amp or meth are both ultimately unsustainable in the long run, at least not without continuing decline in mental faculties and physical health.
I agree that's it's very unlikely you'll be legally prescribed amps as a treatment for your meth addiction. I also think it's worth asking yourself what exactly it is you think are the benefits of using adderall over meth?