In case the Thais have to bring in a beefier aircraft they do have the F-16A/B Falcon. Myanmar does have the Mig-29. One strayed over the Thai border in 2022. The F-16A/B Falcon turns tighter, turns faster, can go faster than the Mig-19, can accelerate faster than the Mig-29, has a lower stall speed, has better vertical, and I believe the F-16 has a clearer canopy with no metal bars causing a blind spot. The Mig-29 scores high on energy maneuverability and capability to gain in a slow-speed close fight, says German pilots who have done combat training operating one against the other. While the F-16 has an advantage above 200 knots speed, the Mig-29 has incredible nose-pointing capability down to 100 knots.
Of course if you don't have the money for proper maintenance and to keep pilots up to date on the latest improvements for that model it won't matter.