YABU to assume that when someone is an “influencer,” their every move isn’t planned, especially as my understanding is that she used to be a marketing executive (there’s a profile still on LinkedIn under her maiden name and screenshots of it are online - no idea what the deal is with saying she was “just a hairdresser,” if that was a hobby or PT work or is just BS, shrug).
Note that she blew up fame-wise, and there was the wedding which kept people interested, and once the wedding was gone, here comes the book, and once the book was out, here comes the baby in just enough time to peak interest again. A baby for most influencers is considered a provider of content, not a burden. Suddenly they’ve got a whole new target market and world of products they can endorse. For example, there’s baby products, post-baby body (usually a huge thing on Instagram), the struggles of motherhood and products to make it “easier,” self-care products to ease the motherhood stress, and then the cleaning she was already known for her. I suspect you’ll see some combo of all of these and can probably play bingo with it. She’s probably been having meetings (she’s managed by an international company - she doesn’t just do this on her own) or just making notes about how to market the baby and herself as a new mother since before her first scan as that seems to be the norm for mommy blogger marketing.
(I’m a ghostwriter. I’ll write anything for enough £, specialize in medical, but I wrote in online marketing for a while and behind the scenes, the “cutest” accounts can be the most mercenary due to the competition being so cutthroat).
To answer your question by actual metrics, no, she hasn’t peaked yet. According to SocialBlade, she’s still gaining followers at a steady rate and has an A- grade so advertisers will still be onto her and the baby will no doubt raise her higher. Her account got a huge boost in followers when she went into hospital, so I imagine she hasn’t shared WHY exactly she was in hospital as she’s waiting to sell it as a cover story exclusive to some magazine. Then I’d expect her to publish a second book after baby.