I can’t comment on that as I have no personal experience with that scenario. A friend of mine who was quite wealthy brought his Thai GF to the states and married her on the fiancé Visa. He got divorced later and tried to bring another GF onto the states without a fiancé Visa and was refused. He had a monthly income of $30,000. She had no skills or property
Unless your GF is a homeowner or has a business in Thailand there is no way other then getting a fiance Visa. And you will need at least $75,000 in cash (in the bank...could be more these days) and you must marry must her in 90 days or....forget it.....The immigrtation officers will know in 1 minute what your GF is about.