some people on this site have told story of being knocked back because insurance didn't specify covid 19 , I just got my visa approved yesterday in Australia about to buy insurance and book asq room which I then have to send to the Thai embassy for approval
U have to get the insurance before U get into Thailand, then show the Thai embassy in your country that U have the insurance before they will give you a Coe to enter Thailand, if U don't get the Coe I don't think U get on the plane to Thailand
yes I'm very sure if you don't have covid insurance at the least then U will not get a Coe to enter Thailand , some visa U need more than covid insurance
Get the extension and a reentry stamp , to get ok to leave Australia just tell them your leaving for more than 3 months , then a fit to fly and Coe , corona test
If U got the is in your country then it is multiple entry and if in the first year if U go back to Thailand now it will be stamped for another year as I have done this