Talking about methamphetamine as a different molecule is not helpful, as Adderall itself is not a single molecule.
Which I suspect you know, as you mention different enantiomers of thalidomide. However you don't point out that adderall itself is a 3:1 racemic mixture of l and d amphetamine.
The real discussion here is the receptor binding affinity of the various targets of the drugs, and how they compare.
The vast majority of adderall prescriptions are XR.
Enantiomers are structurally “the same molecule” (or people often speak this way depending on the context) but with different optical configurations.
There's a whole section, "Single-Isomer Versus Racemic Formulation", in this recent review article titled "Novel Formulations of ADHD Medications: Stimulant Selection and Management" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8412159/
The psychiatry handbook of Massachusetts General Hospital also uses racemic in this context https://www.sciencedirect.com/science/article/abs/pii/B97814...
Also, I can't find any data on what percentage of Adderall prescriptions are XR, have you found anything?
Looks like the LRx database would be the place to look from scanning this report for the DEA. https://www.deadiversion.usdoj.gov/pubs/docs/IQVIA_Report_on...