key is to use your nonO and try to get Thai bank account immediately so you can deposit 800k Thb. But try to pick your city for living since might be a hassle to change banks to new city later.
A lot of my Thai stuff has first and middle and no last name. Even immigration letter for residency that I did today to renew my Thai drivers license has this format. Same thing happened to me when I lived in Singapore. I think it is because my usa passport has first snd middle together and surname is above and it confuses some people. Been dealing with this for 9 years and no issues so far
Be sure to stop at your specific immigration list for the paper that tells you all of their specific requirements. I also had to have map to my house and pics of me inside and outside my place of residency and shortly after I turned in my paperwork I had to be st my house for a videocall so my officer could take screenshots of me at my place of residency.