A few flaws presented themselves right from the outset.

First of all, the show is Stargirl, not Starman. Why does it start with an action scene revolving around Starman's death instead of starting with Courtney, the girl who will be Stargirl?

Secondly, it's not clear why Starman is such a dick to his trusted and heroic sidekick Pat. Immediately after Pat runs into an exploding building and rescues him, Starman waxes on how he needs someone ACTUALLY heroic to inherit his powers. Of course, the real reason is just that the staff is not compatible with him. Surely it'd be easier to just say that instead of dissing your best friend on your deathbed. Perhaps the compatibility issue will be clarified as a bit of a Thors Hammer "worthiness" scenario, but if so it's still not clear how Courtney is any more qualified than Pat aside from simply being Starman's daughter.

Moreover, if they wanted to say that Starman is heroic, perhaps they could heve spent his screentime showing how heroic he really is?

Thirdly, what were the villains trying to do 10 years ago that was so important it needed to be shown to us steaight away? After the villains defeated the heroes 10 years ago, what have they been doing? Just sitting around and scheming it seems. (And apparently also raising a child in their eeeeevil mansion.)

They set up a (boring) character arc for Courtney where she would have to learn to accept her new stepfather. But then that arc is resolved halfway into the first episode -- not through character growth but simply when she is presented with an opportunity to blackmail her new stepfather (but I suppose she's only blackmailing him "heroically"). Following that, there's no character arc provided for her. Overall, the only real conflict is external, and we're never given any sense of the stakes.

Just in general, the writing is terrible and the acting is unconvincing.