My experience re-entering Bngkok after a one-month visit to U.S.:
Set up my appoint at a well-known pharmacy chain via their website. Very easy to do and was confirmed that my test would be free of charge, wtih test results emailed to me within 72 hours. My return flight was on a Monday at 12pm, so my test was scheduled for the previous Friday at 3pm. A week before my appointment, I called the location to verify my appointment and be reassured that I'd get my results back in time. They told me because they (and all other chain pharmacies that offer "free" tests) merely collect the sample, then have to send it out to a lab for testing -- they do not test the sample themsleves as they don't have a lab on site. And because the labs are closed on Saturday & Sunday, they could not "guarantee" I'd have my results back by Monday morning. It could take up to "three WORKING days" -- in this case, possibly five days total. But my flight was on Monday and the regulations stated the test results had to be within 72 hours. I contacted to other places offering free tests and they told me the same. So my only option was to go to a medical clinic and get the test done with same-day results...which is not free. It cost me close to $200. Bottom line: the free tests are not ideal for those flying internationally out of the U.S., who are given only a 72-hour window; you pretty much have to go someplace where you pay (a lot) for the test. At least that's how it was in my city.
Once I had the test results, it was smooth sailing. Check-in at the airport involved the airline checking my test results, my vaccine certificate, and proof of insurance required to enter Thailand. Upon arrival at Suvarnabumi, they again checked my required documents, proof of hotel/test booking, and Thailand Pass QR code (everything necessary is already loaded into Thailand Pass and easily viewble by scanning the QR code, but they wanted to see hard copy paperwork, as well). Going through the documents check, as well as immigration, was a breeze. The two or three people I saw having a rough go of it were people who didn't have everything they needed or didn't have everything in order.
A driver (private car) from the hotel I booked was already waiting for me and was no extra charge; already included in booking fee. I should mention the hotel I booked was not a fancy overpriced one; just a simple but comfortable place I've stayed at before, about 15 minutes from my condo. The room was nice enough for what I paid. I got in quite late (close to midnight), so when I checked in, I was told my PCR test would be at 8am the next morning, and that would be the only time I'd be permitted to leave my room until my results came back by 8pm. I would be delivered three meals -- at 7-8am, 12-1pm, and 5-6pm.
At 8am, I went to the assigned floor for my test...the testing personnel showed up around 8:20. Went back to my room. Breakfast arrived around 9am: two lukewarm fried eggs, two lukewarm sausages (no microwave to heat it up), bread, small salad, and a warm juicebox of orange juice (with no straw to poke in it). Lunch arrived around 2pm: lukewarm Thai beef, lukewarm white rice, two slices of cucumber, and some Bua Loy (which was my favorite part). Dinner arrived around 6:30: chicken fried rice (actually hot), another lukewarm fried egg, small salad, and bread. By 8:30pm, I still had not received my test results, so I called down to the front desk. They told me my results came back at 5:30 and were negative. I asked how I was supposed to know that, since no one called me or knocked on my door or sent me an email. They said, "We apologize. You are free to check out if you wish. You can collect your test results at the front desk." Having lived here for quite some time, I shouldn't have been surprised.
Upon arriving back at my condo, seeing as how I had my luggage with me and had obviously just come back from traveling, I was directed to the juristic office to show them my test results before being permitted to go up to my unit.
All in all, a smooth process, but a lot of hassle. And left with the impression that the SHA hotel will probably do only the minimum to ensure your pleasant stay. Certainly not going out of their way to provide you with the best meals or timely service. [name of hotel intentionally excluded so not to run afoul of the dubious libel laws here...but it's at the end of Soi 11]