This kind of sums it up...

She is way too nicety - nice on screen after being stranded from her home planet. (I suppose the writers wanted to appeal to a young genre )
The comic books captured her emotions far better as being stuck alone on a strange alien planet (albeit with incredible powers.)
And her pretend sister gaining super powers?
Come on! Get out of here you poor scriptwriters.

Just imagine a favorite home cooked dish democratized by a large corporation with boards, committees and focus groups  first coming out in packaged frozen microwavable form,   and also as part of a school lunch menu using usda approved ingredients  and also subject to the dietary board that regulates the proportion of fats, protein sodium sugar and fiber content to assure that the product meets the recommended daily requirements..   Can only hope that the mass market version inspires a few creative spin offs

It's heartbreaking. I also love this character in the comics. I was cautiously optimistic when the show was announced, but I realized there were many ways for it to go wrong. When the pilot was released I was freaking overjoyed. Great actress, great costume, great action, it was like a dream come true. Almost right away the quality of the writing proved poor, but the tone was awesome.

The super-promising start is why the show is such a massive disappointment. If it had been crap from the beginning, then meh. But they got so many things right initially that the steady movement away from those things in subsequent seasons hurt. A lot. First it became a team show, sidelining the supposed main character. Then the plots started getting way too silly. Then the action dropped off a cliff. Then it went full uber-woke in the most hamfisted way possible. Then they changed the costume and gave Supergirl bangs. Then everyone became a superhero. Every one of these major changes was a move in the wrong direction. Combined, they made Supergirl the worst fully funded broadcast TV show I've ever seen. The last two seasons were unwatchable. What a terrible loss.