So, you don't get a test result via e-mail? During my Phuket Sandbox in October, I received an e-mail result, and I assume the hotel received something as well.
Honestly, I found it easier to use one of the main Thai ones. Then again, I went/am only going for just under a month. If you are going for longer than 3 months, this may get expensive however.
I transited through there (NRT) mid November. As long as you don't have to collect bags, you are good. When we landed, they herded us to an empty terminal for the Covid document checks, then bussed us to our departure terminal.
I went with a Thai female friend (who is now my girlfriend). She did all the talking. All they really wanted to know was what account will most of the $$$ be coming from overseas, and also to have a look at my passport. No visa, just 30 day exemption. I think she saw the many entry stamps.
But I honestly think it is the mood of the person you speak to on any given day.