If you are interested in classic Muay sports, the father sports of Muay Thai, then I suggest Muay Chaiya in Bangkok for example Kru Praeng at
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Unfortunately that is in the far outskirts of Bangkok, with not even MRT/BTS close to it.
However there are two schools along the Air port link.
Put "muay chaiya bangkok" into google maps ...
About Pattaya, I have no idea. Muay Chaiya, or Muay Thai Chaiya is a very self defense focused Muay Boran style. Boran meaning "ancient". Muay Boran is the umbrella term for the classic Thai fighting styles from which Muay Thai was derived.
Muay Chaiya is famous for its throwing techniques and joint locks, it is basically the BJJ/Aikido of Muay Thai.
About Pattaya: I have no clue.