What are the requirements for Philippine and US nationals to visit Thailand for leisure in October or November?

A traveler from the Philippines and their fiancée from the US are seeking guidance on the current requirements for visiting Thailand for leisure in October or November. The last attempt to visit was canceled last December due to complications with Thailand Pass and quarantine regulations. As per a comment, if vaccinated, travelers need to provide proof of vaccination; otherwise, a negative antigen test within 72 hours of the flight is required. Although no insurance is mandated, obtaining travel insurance is highly recommended.