When first visiting a major city it has been my experience that it is best to take (safe, inexpensive) rail from the airport to centre city. Then, take a cab to one’s local destination.
To do that comfortably you must first “pack light”.
BTW, did you know that the word ‘impediment’ comes directly from the Latin word for baggage? You have to give it up to those crafty, wise Romans!
For example, the last time we visited Milan we landed at Malpensa with only two manageable bags, hopped on the train and found ourselves in Milano Centrale in no time. From there, a short cab to our hotel.
I’m sure you’ll find it to be the same in Bangkok; in fact I once saw Tony Bourdain recommend exactly that on one of his TV shows.