If you have only just arrived in Thailand on a Non-O you should be able to approach bank , get approved and put in the 800K required to fulfill the 12 month
Extension .
Yes 30K baht sounds about right for the Non-O to be
Organised incl a bank account .
It could cost you possibly 60 K to get the whole thing done , if you leave Thailand & re-enter or your current 90 day Non-o expires .
If you want to stay long term & get a multiple entry , in 2025 , 30K is the deal using an agent