Is there something like Netflix for books / ebooks?
I think Amazon Prime offers such possibilities.
There's Kindle Unlimited, which costs 9.99 a month. The first 30 days are free.
There's Kindle Unlimited, but it is not included in Prime.
At the library of my city there's an account for e-books free of charge for the account of analogue books. Of these, the library association has a lot on offer and you can borrow 15 books at a time and determine the loan duration yourself. Maybe there's this offer near you too…
Prime includes a "slimmed down version" of Kindle Unlimited.
Kindle Unlimited is completely overpriced subscription with weak offer!
How can you recommend it?
120 euro per year and so a weak choice of books - that is a usury price!
No current bestsellers, only relatively little-known books by well-known authors, and mainly just self-publishing scribbles from any hobbyist authors. This is NEVER worth 120 euro per year!
How can you fall for it?
Kindle Unlimited is rip-off for usury price!
The best and cheapest way to read really good eBooks - even many current bestsellers - for free is the Onleihe the city libraries http://www.onleihe.net.
You can borrow and download eBooks online for free if you have a library card.
The library card is usually free for teenagers, it costs a small annual fee for adults (about 10 - 30 euro per year, depending on the city)
The onleihe can be used on PC, tablet, smartphone and with all ebook readers (Tolino, Pocketbook, Kobo, …) - except Kindle. Kindle can't do that because Amazon prevents this by restricting the format of Kindle Ebook readers.
Here are many more tips for free eBooks:
https://www.lesen.net/kostenlose-ebooks/
It's not worth it to pay the usurious price for Kindle Unlimited.
First of all, let's get out of it, that's not good for your blood pressure. Second, I recommend nothing here, but answered the question that is whether there's such a thing. Since I know only Kindle Unlimited, which I do not use myself, because I like my books analog.