Actually, Ms. Namak IS one of the sources I mentioned. To quote her:
"From
*****
/2022. All insurers will not cover if you re tested positive covid asymptomatic. If you re not fell sick then the thai authority’s forced you to stay in hospital, hospitel or hotel for quarantine.
The insurance company will pay the expenses related to the medical treatment you need due to positive covid . Not the room or accommodation charge.
The insurance company will Not cover for close case contact either.
Right now if no symptoms they will push you to do hotel isolation or home isolation."
one more question if you don't mind: did they ask for a reason for the extension (can't fly back home etc.)? As it officially is a covid extension, after all...
In that case I guess it makes sense to apply as close as possible to the end of the current visa termination date, in order to potentially prolong it by a few days via the 7 day stamp?