Anywhere in the world, resorts are resorts.
Your experience will be directly related to cost.
Thailand is no different.
Thailand has resorts that cost anywhere from US $500 to US $1000+ a night.
That is not cheap, however, you are paying for the experience.
Same as any other country in the world.
If you want a one of a kind 5 star experience, it is going to be even more expensive in Thailand than other locations in the world.
While there are cheap accommodations, don’t expect a 5 star experience for that price.
You will be seriously disappointed.
One good thing about most Thai resorts?
If you show up in person, they will show you an actual room before you have to pay to see if the room meets your standards or not.
5 star resorts are 5 stars for a reason and they are not cheap!