My plan would be;
Get a non-O e-visa before you leave. You only need to show the equivalent of 400k in your home country account, together with a copy of your marriage certificate, etc.
Sort out a Wise account that you can eventually send money to your Thai account from.
Enter and get a 90 day entry.
In the 1st 30 days re-activate your bank account, or open a new one, and deposit the required 400k.
You will need a TM30 when you extend. 90 days is irrelevant.