if your entire site is exclusively about bachelorettes then it already has topical authority, so this is the problem...
The problem could be that it has too few pages (along with also not being authoritative, trustworthy, or aged enough, or any combination of these), or that the pages are not unique / well optimized, or that your site doesn't have enough (normal) authority (ie. DR)... or that the competition is strong and you're targeting wrong / tough keywords... it could also be that google simply refuses to rank the main page for whatever reason (keyword cannibalization, low authority, poor / no optimization, etc)
But anyway, what do you mean by "main page is struggling"? Like, it's struggling to rank? Or it already ranks but it doesn't get (enough) traffic? Or it doesn't even get indexed? What exactly do you mean by that?