The classes in Bangkok? If yes, you're one of the very rare exceptions who deserve it. Most barely attend the online classes. A 5-year visa for a monthly online class that only a few follow isn’t exactly a strong motive, which is why more and more embassies are now refusing it.
It's better to shift to another soft power, such as Muay Thai. This seminar will likely be rejected everywhere soon—9999 THB for a five-year online monthly class? (Yes I know you can attend, but no one does). No wonder it's being refused.