What are the key travel requirements for entering Thailand during the Covid-19 pandemic?

Last night going through immigration at. Thailand was stressful enough. I don't know if my situation is relevant tp future travelers, but I will share a a few observations. My COE was granted on Wednesday and I flew out Thursday night. I risked missing my flight because Thursday afternoon on the way to the airport I received an email from RTE Seoul telling me my Covid lab report, although it said in English, RT-PCR negative, because the rest of the report was in Korean it was not acceptable and I had to go to an affiliated brach of the original clinic and get a report totally in English. It was required I have a medical certificate as well as a fit to fly document signed by the doctor, obviously also in English. Airport check in was quick and painless. Everything went well through immigration in BKK until my last checkpoint where an obstacle came up- the RTE in Seoul had not submitted my name on the "list." After about a 20 minute wait it was somehow resolved. (Really, how could I have obtained a COE if I wasn't approved?) Speaking of COEs, that is definitely the most important document to have a copy of.

Take home points, for me, all other things being equal, I would fly out earlier in the day. Stress gets more more overwhelming as the day rolls on. Make sure your Covid test report is entirely in English. When you pick up your COE kindly remind the RTE employee to submit your name to immigration, and perhaps follow-up with a friendly email reminder before you leave. Copy of COE document. You need a medical certificate as well as a fit to fly. The above all pertains to my experience traveling from Seoul.

Good luck to all.