Rather than looking for some kind of all-in-one solution, that is sure to compromise on features, why not just download the novels you want, and then use any reader you want?
I agree that Rudy’s flaws are central to the story, and that’s why I wrote “if you can accept it” rather than “if you can tolerate it.”
My main point was that the emphasis on sex, how it’s presented, and the extent to which this is interwoven with Rudy’s personality, will obviously be a turnoff to some.
Rudeus is a really, really flawed character, and it definitely means that the anime and LN won’t be for everyone, but if you can accept it, there’s a lot there to enjoy. I agree that it makes it difficult to recommend to people.
I’ve read up through volume 19 of the LN, and though I love the series, I’d absolutely prefer if Rudy’s libido were slightly less of a focal point.