There’s no such thing as too many books.
Controversial opinion: there’s no such thing as too long a book or series. Sure, there’s an upper bound, but I have yet to find a series that I like reach said bound.
If you want some science fiction and fantasy series, here’s a whole bunch:
https://books.bookfunnel.com/March2025SF_FBoxedSetSales/bexwbkn1qr