How do I transition from an education visa to a Guardian visa in Thailand?

In THEORY you aren't getting ANY VISA 😮

You are now currently on an Extension of Stay based on education, (not an ED VISA) and all you'd be doing would be cancelling the extension of stay with documentation from your school saying on xxx date you stop and then immediately applying for a NEW extension of stay based on raising a foreign child enrolled in a school here on an ED visa by showing the documentation and the proof of the 500K baht in a thai bank account in your name only for 30 days before you apply for the extension.

You're just doing a "reason change" from one extension to another extension, not anything to do with a visa..

I don't see any reason why it can't be done

BUT

I'd sure talk to your school as well as to the immigration office where that extension is issued so they can confirm they'll let you just "change a reason".

Otherwise you would have to cancel that ED extension, leave the country, either buy a 90 day Non-O visa based on raising a foreign child at a thai consulate before you come back

OR

come back on a free entry stamp and get the 90 day Non-O visa issued inside the country for 2000baht and then do the year extension for 1900baht after that