yes, it is available in private hospitals. i ain't sure if price i heard (10,000 baht) if it is correct or not. you should call or visit a nearest hospital around your place to check for correct cost.
Normally for medical visa difficult to change to any type of visa. Try to apply covid-19 extension. Immigration have extended it until May 29, 2021. Using covid-19 extension then you will be able to swap it with another type of visa.
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