I don't think you know what you're talking about. There are multiple patents pending on modified kratom alkaloids.
https://en.wikipedia.org/wiki/Deuterated_mitragynine?wprov=sfla1
I've read about others but that was the first one I came across in development.
Psilocin pro-drugs are another category with multiple patents pending, Mindset Pharma holding a few.
https://en.wikipedia.org/wiki/MSP-1014?wprov=sfla1
Here is another patented by Reunion Neuroscience.