Women flit between wanting to show themselves and wanting to cover up. They want Chad to see of course, but it depends on their attitude towards nonchads.

Ideally they want nonchads to be mesmerized by them and no further. They like to imagine they are a pretty princess and everyone thinks they're beautiful and nothing more, except Chad of course. Attitudes also differ depending on things like race or weight. If a white guy says anything he is viewed a creep, if a black guy scrunches up his face and goes "MMH HMM DAT AYAAZZZ NIGGA YOUZ A HOT BIATCH" (or whatever the african american verncaulr is this season) it is viewed as funny and harmless. If a fat or old woman wears skimpy clothing it is safe edgy to "male gaze" and say she looks great, but if it is an actually attractive woman you have to tread on eggshells.

The media influences this a lot and there is no rhyme or reason to it. It is not clear whether they want men to look at them and be attracted to them or not or what is the right and proper way to react without hurting their feelings.

You might be able to get away with saying something ambiguous like "wow", but the best option is to say nothing at all, it is cringe to state the obvious as if you're the first person to notice she is attractive. Don't even compliment her clothes or hair despite the fact they put an inordinate amount of effort into it. Talk about something else and say you admire her intelligence and knowledge or something cringe, which they know is fake but proves you're not just some mindless ape. Women are put at ease by men who focus on an interest as it shows your intent, though it can't be your autistic hobbies, it has to be something appealing to women like music or food and you have to avoid "mansplaining" or anything that makes them upset, as they very easily get upset.

My stepuncle told me that you should listen to women but never believe them.