I don't have iOS but you can see trending hashtags on the web so maybe there's an equivalent on the app? You could also see all the latest post from you server and the entire Mastodon.
The best way to diversify the timeline for me is to directly follow tags of things you like.
Pumpkin or pumpkin spice? Or both? I've had a pumpkin pie for the first time a few years ago. Although not my favourite it's not too bad and I'm not a fan of pumpkin at all