I really feel like I've made it,” says the actress and star of the new Disney+ series “Agatha All Along.” “The sad thing is I bought it and put it together myself, and I loved every second of it. Still needed to look at the instructions.

That approach pays off in the nine-episode series, a magical quest that takes its tonal cues from Hahn’s big, brassy, cock-eyed performance. (Critics screened four episodes in advance.) Marvel has been in something of a creative and financial slump as of late,