How can I change from a Student Visa to a Work Permit Visa in Thailand?

a lot u just cannot change .... cost, staff, running company costs ..... filing tax returns and accountant charges....

Whether you can go from an ED visa/extension to an in country 90 day Non-B visa totally depends on IF your employer can meet the documentation requirements to apply for the Non-B visa inside the country at the immigration office. <- you need to be talking to your new employer AND the immigration office you'd be dealing with

The way it works IS

You would get a letter from your school saying you stop studying on xxx date, go to the immigration office cancel your ED extension and then immediately apply for a 60 day covid extension. THEN get the documentation together and go apply for the 90 day Non-B visa at your immigration office

Again this process should only be undertaken AFTER you have confirmed with both your new employer and the immigration office that it can be done