but I'd kind of rather they put stuff other than books on the carousels. Books are my competition,
No, they're not.
When your own books are doing the right thing, the also-bought and viewed sliders should first off have your own books on them.
Other books are what your readers are reading as well, and this is not competition.
If you release every 3 months, that's 90 days without a release, and for a lot of people, that's 30 to 90 books they read between yours. None of them are competition.
Sure, the order people read in might not favour you, but the people who read a lot, and read your books, will read you sometime. It's still not competition for someone else to be read first, as long as you are read.
The whole authors compete thing doesn't hold water. The market is huge, authors release much slower than readers want, and there is plenty of slack in the system for everyone.
The same sliders you see as promoting other people's books are the ones who promote yours to the readers of those other's books. It works both ways.
My current book getting on the first also bought page of say Glynn Stewart's new release, always boosts my book. And my book being boosted, boosts my catalogue. The only thing I wish about Glynn is my slice of his audience was bigger, but I know we share readers. So when people miss my book coming out, they often find it on his. And I've no doubt since Amazon don't send out follower emails anymore, a lot of his fans might be seeing his new book on mine.