@Thomas ********
you MIGHT <- as in totally depending on the immigration office be able to cancel your current extension and apply for a 60 day covid extension as long as you do it before the current program runs out on Jan 25th. That would buy you time to get your money seasoned so you can apply for a new yearly extension based on raising foreign children here.
Keep in mind ONLY the very first year extension allows the 500K baht to be in an account for 30 days, every year after that is 3 months <- that's three months date to date NOT 90 days.
All you are doing is cancelling one extension and applying for a new one so it does not count as 'starting over with a new non-O visa and first extension'.