You can't really toggle this off from Instagram's side, but what tends to help is managing what's actually in your phone's photo library. The story camera pulls suggestions from there, so if you've got thousands of old photos cluttering things up, that's what you're seeing. Moving older stuff to cloud storage or a separate folder on your device can help reduce what gets surfaced.
Another thing worth trying: go into your Instagram app settings and clear the app cache (not data, just cache - that keeps you logged in). Sometimes the suggestion algorithm gets a bit stuck on old patterns and clearing that out resets things. You might also want to check if there's a "Recently Deleted" or archive folder on your phone pulling old images into the suggestions - some phones do this automatically.
If you're still seeing the same ancient photos after that, honestly the nuclear option is just being selective about what you keep in your main camera roll. It's a bit tedious, but once the old stuff isn't there, Instagram's got nothing to suggest.