Here's a good article. I'm a scuba diver, so most of this is common sense to me. Your odds of being killed in a shark attacked are better than winning the 6-49, but still pretty low at 1 in 4,332,817 according to the article. I've been in many places with sharks, gone on shark feedings and observation dives, been snorkeling with them and not one bite. Granted I do have some training, but still. Real sharks are not Jaws. Yes, there are many horrifying true stories out there, but the odds of being killed are about .000025% so take normal precautions and enjoy your trip. You could be struck by lightning tomorrow, but that won't stop you from leaving home. Odds are, if you stay away from trees and electricity conductors in a lightning storm, you will be fine, like every other day of your life.
The 1st, 3rd, 4th, 5th, 7th, 8th and 9th bullets are especially good. Never heard of the tan line one before!
https://www.smartertravel.com/shark-safety-tips/
Regarding Thailand, I did a liveaboard trip there and saw sharks, although they were the relatively harmless type. Since we were about 24 hours from land in the Andaman Sea, they probably weren't used to divers and were very skittish.