It only takes a week or two. My girlfriend at the time had her interview for a visitors visa in two weeks after I submitted the application. However it was denied. This was October of ,2022.
if you are going to marry a Thai woman in Thailand, make an appointment at the American Counsulate, I seen your profile, to get an Affadavit of Freedom to Marry. Take the divorce document with you. Then you have to get the Affadavit certified by the MFA, the Thai Ministry of Foreign Affairs. I can't remember if the Affadavit is in both English and Thai. If in English it needs to be translated before you bring it to the MFA.
Each bank makes up their own rules. I tried 3 banks before I was lucky enough to open up one with Bangkok Bank. Only because Immigration gave me a letter notifying the bank I was applying for a Non O based on marraige. Some other people are lucky and able to get one on a regular tourist visa. All you can do is try and if not successful use an Agent to open one for you. Good luck.