Just finished a binge of this subgenre and the dynamic is everywhere now, but it can feel so repetitive. The ones that stand out for me ditch the instant-perfection nanny trope. Like, in 'The Nanny and the CEO' or whatever, she's not just 'feisty'—she's got a whole paralegal career she's putting on hold, and he's less 'protective' and more 'control freak who has to learn boundaries.' That friction creates the actual protectiveness, not some alpha-instinct nonsense.
Another I'd throw in is 'Nanny for the Neighbors' – it's a why-choose situation, which flips the script. The 'protective' element comes from multiple guys, sometimes clashing with each other, while the heroine's independence is literally her job; she's running a small business out of their home. It gets messy, which I prefer over the polished billionaire estates.
Honestly, skip the ones where she's just stubborn and he's just rich. Look for where her independence costs her something, and his protectiveness becomes a problem he has to solve, not a virtue.