The child cannot be born in U.S. then.
First principle is to protect the child. That means marrying before the child is born so that the child has an easier path to U.S. citizenship. Presumably through CRBA, but if necessary, through IR-2. Out of wedlock births to non gestational U.S. citizen parents sometimes produce a nightmare for the child.
So K-1 is out.
I am normally a Utah zoom advocate, but it takes 2 years to get a CR-1 visa. So follow the Thai process to get married, since the child will be in Thailand for at least 18 months, and you want to be certain the marriage is recognized under Thai law. Especially if the CR-1 is denied or goes into extended processing.
Fewer than 5 K-3 visas are issued per year. You can try, but you will have better luck playing slots in a casino. When Congress established K-1 and K-3, the intent was these would be fast turn around visas, end to end 90 days usually. So K-3 was superior to CR-1 and K-1.
Over time, USCIS and DoS corrupted the intent of Congress to make K-3 take as long as CR-1, and then did the same with K-1. Indeed K-1 now takes longer than CR-1.
CR-1 is the superior visa, and your wife should wait until your 2 year marriage anniversary to enter on her CR-1 visa.