I can't work out a way to link to a specific bit of those Facebook reels, but I've just seen one that is a perfect example of what I was saying a few days ago.
A ridiculously cute baby is being put through her paces by an offscreen adult, and the voiceover is talking about 'goals' to be reached by particular ages (the baby is about 12 weeks old). One goal is 'upper body strength', which can be achieved by 'tummy time' facing a mirror, which is sold by the influencer, and structured games where you dangle something above the baby for her to reach. Another is 'eye co-ordination', which involves swinging the dangling item (also available to buy) from side to side so the baby follows it with her gaze. There are times attached for these activities. Then there's the bedtime routine, which involves feeding, burping and changing, followed by a wipedown with lotion (guess where you can get that), and swaddling in a velcro-fastened garment (ditto). The swaddle is 'transitioned' to a sleeveless version when the baby can roll over, and again, the influencer will flog you that, too.
None of that is different from what I'd think any parents do (swaddling wasn't my thing, but does seem to be the fashion). We might not have called it 'tummy time' or timed our 'structured activities', or even worked towards our 5 week old babies reaching 'goals', but it all looked very familiar. I can't see it doing any harm to the baby, but I do think it could make anxious new mums more so, and I have reservations about the sales opportunities, too. The comments show the usual competition too. 'My baby could roll over at 3 days old', 'Oh, that's nothing - mine was doing it in the delivery room, and could talk at 4 weeks', so it's an open goal for influencers.