sure. things that work in comics, won't necessarily work for TV. Same with movies. Movies with 2 hour formats, Comics with long monthly runs, or GN. and TV shows with their seasons.
The supergirl changes most a little sense though at least. And very clearly has many elements of the character and figures around her.
Supergirl is inherently a fish out of water story. While Clark was a baby and grew up in Kansas. Supergirl was sent to Earth at 15. she GREW UP on Krypton/Argo City. (Shes actually older then Superman chronologically. )
now, normally, this is written as, shes Alien, and knows little of human culture. Unlike Superman who is human first, and alien second. Which is one of those things, that Man of Steel totally fucks up, and why its wrong to suggest Superman is Kal-El, and can't understand humanity. no, thats Supergirl. SHE is one that struggles with that.
In this new TV show, they seemed to have blended Kara, with Linda Danvers a bit though. The third Supergirl.
Linda Danvers was a brown haired country girl... who almost killed in comic book shenanigans , then bonded with the "Matrix Supergirl" (a shapeshifting clone made by alt Earth Alexander Luthor).
Took on the identity of Supergirl.
Kara has actually been dead for most of her career.
So the smalltime girl who gets powers and trys to live up to the inspiration of her "cousin", is Linda Danvers supergirl.
So while it may blend bits of each Supergirl... its not a stretch at all.