Patryk Solarz you have until the 25th January To apply for the COVID extension . If it's your first time getting the 60 days extension it will start on the date you apply
If you plan to overstay just remember if you get pulled up anywhere even on your way to airport . You'll be in big trouble . Is it really worth the risk for a 1900baht extension that you can get?
You can probably go back to immigration on the 25th January ( In which the covid extension ceases for now ) and get another covid extension and pay 1900baht instead of taking the risk
It took you 2 weeks to reply.. However you may be allowed to enter Thailand being positive but are you allowed to board the airline with the same result?? .
So is that a risk you are willing to take .... Good luck with it all ....