I use a tax accountant to file my US return. His office now has Thai tax accountants so they also filed my Thai tax return.
The money I brought into Thailand was a combination of US Social Security and money from savings. US Social Security is not taxed in Thailand. The excess came from savings which I had prior to January 1, 2024 so it is not subject to tax. Also, I was told that the amount I pay for my Thai insurance is also deductible as long as it is through a Thai company.
In the end I had zero Thai tax liability.