More fake news - "Arrivals from countries deemed low risk – China, Vietnam, Taiwan, South Korea, Australia and New Zealand – will only have to quarantine 10 days after the plan wins approval, Kiattiphum Wongrajit of the Public Health Ministry said." So the plan has not been passed and no guarantee it will pass.
From my personal experience, pre-Covid doctors were aware the immigration bureaucracy was looking over their shoulder and would come down hard on them if they abused giving medical extensions. This is likely a new request of this psychologist, so he/she may not be aware of the road they may be going down.
At the top right there's a magnifying class/search icon, best you search the question as it has Benn asked a shitload of times and you're really not going to make all these nice people have to write it again for the 1000th time?
I had surgery on my Achilles tendon in Thailand and Was only able to get a brief medical extension, although I was still having problems ambulating. I discussed the issue frankly with my doctor, and he said the bureaucratic authorities were constantly looking over the doctors shoulders to make sure they were not abusing the privilege. That is only my individual experience and I don’t know if the situation has changed, but you might want to check with your doctor soon after the surgery in order to have more options.