@Mark *******
in the 9 years that I have lived here (admittedly only Chiang Mai) I have only found one farang physician. There may be more in Bangkok.
The thai government doesn't want or need foreign physicians. The certification bureaucracy is way beyond anything you have ever experienced. Pretty equal to US accepting foreign MDs...pre-covid. Requiring Years of training, residency.
And quite frankly the level of training for thai MDs is incredibly high.
For eg my orthopedic surgeon did his residency at Mayo. My husband's neurologist went to Harvard. GP - Stanford. All the thai doctors I know spend the majority of their time in the NHS. My impression is it's mandatory.
Set up an actual practice probably is not going to happen.