It seems the true number was 18 after all, like Hamas was saying, and not 54 like Israel was saying.

https://www.nationthailand.com/thailand/general/40032323

Also Hamas has already reached an agreement with Thailand to release the Thai hostages but Israel is so far refusing to cooperate with their release.

https://www.bangkokpost.com/thailand/general/2673106/hamas-ready-to-free-all-thais

Thai gov says 18, don't spread misinformation