If you have a sealed class with only object implementing it you could make it an enum as well:

enum class Foo {
    A {
        override fun execute() = println("A")
    },
    B {
        override fun execute() = println("B")
    };
    
    abstract fun execute()
}

Yeah, that's totally true. I just feel like at some point I'll regret this decision and need stateful classes.

Yeah it's less flexible.

I just get paranoid with these that I'm doing something I'll regret later. Heh.