Sejic did a redesign of Karen's costume a while back and I really like how he handled the window in it;
DC Power Girl.jpg
The window is higher than usual, smaller than usual, and looks more like some standard fashion cleavage while still retaining the basic aesthetic of PG's costume. That's how I'd like to see it handled. Not just in film but in everything.
The rest of the suit is great too, in my opinion, but it's the window I'm focusing on for this discussion.
Oh Karen dealing with sexual harassment is definitely not A-plot material. It's a viable part of the character's conversation but not what you build a whole film around, unless you're trying to do a *very* different kind of superhero movie, anyway. I think the Thor comparison isn't too bad an example but it's usually too subtle for what I envision; Thor's looks don't really get in his way, or make people underestimate him or talk down to him or anything like that. It's just there, but Karen's looks are something she has to work her life around (to a point).
The Captain Marvel film, despite having all the subtlety of a sledge hammer, hit the right balance, I think, where gender, objectification, etc., played into Carol's interactions in a realistic way without demanding all the attention or distracting from the main plot. Granted, that film didn't handle the topic with any nuance or grace but I think the impact and amount of screen time it took up, if we discount the execution, is about right for Karen.