The answer to your question of no, you can't you switch from a yearly extension based on marriage to one based on employment inside the country, ๐
To do that, you'd cancel the extension you're on, exit the country, either get a non b from a nearby thai consulate or exit come back in free stamp (visa exempt) then apply for the 90 day Non-B at your immigration office
What is your reasoning behind doing that?
Unless you are about to get divorced, I would say stay on your yearly extension based on marriage and hold your work permit just like you are now...