You could possibly be better off with a different visa depending on your needs and income.
I am a U.S. citizen and married my Thai wife 35 years ago in the US.
We did take our USA marriage certificate to Thailand and did what you propose. We did it in 2023. We did it in our own without paying anyone for help. Very frustrating and difficult. We can offer the correct advice if you want it.
The most difficult part was our own USA embassy in Bangkok. Extremely uncooperative. The worst part is that my Thai wife became dual citizen 20 years ago, so it is her country too.
We completed marriage visa.
We now live in our modern style house in Ratchaburi half the year and the US half the year.
I am a US citizen, my Thai fiancé (at the time) did all the work without my help to get passport and complete all the steps to get her fiancé visa. We went to US, married and then I changed my last name to her’s. I started at the driver’s license office and they pushed back hard. I simply stated that if they don’t help me then I will pursue discrimination based on gender. After a 3 minute huddle in the back office, they changed my last name. Then off to Social Security office to do the same. Then notify credit cards, banks and all.
Good luck. It helps to be knowledgeable, correct and assertive.
I under you are doing it in Thailand and I did it in USA, but I am hopeful my experience will give you the wings you need to fly.
US citizens like myself cannot get Thailand tourist e-visa while in Thailand.
Go to any country and apply for e-visa while in the country you chose to visit.
December 2023 I went to South Korea for a 4 day family vacation and while there I applied for the Thailand 60 day tourist e-visa. All the paperwork was completed 2 days into my trip and it took an additional 2-3 weeks for me to receive my e-visa via email.
As per the application process I had to prove I was in South Korea by showing my flight purchase and showing my South Korea visa in my passport.
Activate a 60 day tourist e-visa. I am a US citizen, senior citizen and wearing proper clothing (not dressed as if I am at the beach). First land border crossing in years. No problem.