@objc write runtime really works?

Can I write @objc field in Swift runtime or not?

This post says, I can, but not sure:

How to set a member variable value using reflection in Swift?

It says with @objc, reflection is possible in Swift, but in my code I can not assign, it raise error for me:

Value of type 'Organization' has no member 'setValue'

if let o = obj as? Organization {
    o.setValue(value, forKey: key)
}

I applied @objc for many field in Organization. What is the problem?

final class Organization: Model, Content {
    static let schema = "Organization"
    
    @ID(custom: "id", generatedBy: .random)
    var id: UUID?

    @OptionalField(key: "fbId")
    var fbId: String?
    
    @OptionalField(key: "name")
    @objc var name: String?