Have you been following the same accounts for a while now, or did you just start following new people recently?
What you're describing is pretty normal, especially if Instagram's algorithm thinks it's already shown you everything "relevant" at this point. The reels feed works differently than regular posts: it prioritizes content based on what you interact with, but if there isn't enough new material from the accounts you follow or similar niches, it starts recycling. Plus, some creators post less frequently than we'd expect, so genuinely new content is limited.
What you can try: follow new accounts in topics that interest you (the more sources, the more variety the algorithm will have to work with), actively engage with reels you haven't seen before even if they don't totally appeal to you at first, and try using the "not interested" feature on repeated reels so Instagram knows you've already seen them. It also helps sometimes to mute certain creators temporarily if you're seeing too much of their content. If none of this works after a few days, try completely closing the app (not just minimizing it) and opening it again - that sometimes refreshes the cache.