They are on this website, lmao
That said, agreed. She never struck me as the flirty type, and the few occasions where she did something hot (like in their video for Last Resort, with the see-through shirt) were less "conscious decision" and more "fashion choice that can be perceived as a thirsttrap".
Also, isn't she like very Christian? I remember seeing something like that in one of her videos, or maybe online, which is also why she never cursed up until their solo project Concrete Castles.
It also isn't like they are trying to hit the mainstream - Audra openly spoke about refusing a chance to do American Idol to focus on F211 and Concrete Castles, and if you have ever listened to CC they (especially their first album) take a lot from sources that the modern American audience doesn't know what to do with, like pop-punk, nu-metal and trip-hop - how many modern Americans will listen to that combo unironically?
If they wanted to go pop they definitely could, and would probably be more successful at it than their fellow YouTube cover artists Halocene, but they chose not to (which I respect much more than the alternative).