It's just the usual initial curiosity thing that drove her initial subscriptions. She's putting out a stupid joke (pussy == cat..get it? get it?). So she will see a giant drop-off in the second month, because as you said, people will now be expecting to see glimpses into her private life.
She will adapt though. She's now got a taste of the higher-than-expected easy income from this joke, so she will adapt to what her audience wants over time because she knows this cat thing is already dead. In this case, she'll shift into starting off posting general life pictures, as you had pointed out. Nothing interesting, but enough to keep some simps paying. But then she will be wondering how high can this easy income get, which then she will start exploring posting pictures of herself (more selfies) in provocative ways e.g. a picture of her biting into a large crispy corndog. It won't be overly sexual by any means because she seems so paranoid about maintain this fake trad thing.
Since she is very insecure about her body, she will never go beyond that. She will never show skin ie, bikini, short-shorts. At most she will do what she is doing on her IG wears page ie. tight jeans and some cleavage. That's about it.
It's kinda funny because from the clip i posted, the young Brittany said she was open to doing porn and doing nudes. Back then though however there was no "classy" site to do such a thing. If the young Brittany had that, things may have been different. She probably would have been doing bikinis and some nudes.
