Your country might write a courtesy letter to Thai Immigration to 'transfer' your active visa status to the 'new' or temporary passport for a fee. I had this done for me when I got a new passport in Chiang Mai. You cannot just 'upgrade' because you got a new passport.
If you are positive before your flight everyone at the clinic, your home, the airport, and all those near could be infected. How could you have a conscience flying if you were positive before boarding?
Eliminate that 14 quarantine requirement if I am already negative. If I am negative I am not contagious. Looks like Cambodia is copying the Thailand quarantine playbook for money too. Not playing that game. It is a start in the right direction, but when the complaints begin to happen about quarantine and wasting money Cambodia and Thailand will get wise They have to get wise they need the money..
A sign of good things to come, hopefully. Requirements seem reasonable and responsible for the traveler. I am sure more countries will be added in the near future.