The second reason why Sabra does not work as a character in a marvel film. (Besides the obvious that she's Israeli propaganda) is that she's visually aligned with protecting a nation. Any hero in Marvel has always been known to protect the world and galaxy and universe and multiverse as a whole. The heroes of the Marvel cinematic universe always strive to protect everyone no matter their nationality, race, gender, sexuality etc. That's the whole point of being a hero.
Sabra contradicts that. She's a hero aligned with a specific nation who will save everyone but a minority. As far as I'm aware she's presented as an antagonist for the Hulk. She makes no fucking sense whatsoever.
(Im using the broad definition of hero here so don't come at me)
Also, if you're deadset on watching brave new world. PIRATE IT.