@Andy *******
Yes you’ll have 90 days and can apply for one year extension of stay based on your Non O visa.
(Not a one year visa but a one year permission to stay based on your Non O visa.😉)
As your embassy doesn’t offer to provide you an affidavit letter to confirm your income, you’ll need to prove the first year yourself by banking 800K baht in a Thai bank. Has to be seasoned for two months prior to your application, so within the first month you’ll need to open a bank account and transfer the funds.