If you skip updates long enough, someone might find a security hole, and if you’ve skipped the update that fixes it, you’ll be able to jailbreak it, install koreader, read epubs without conversion, use the filesystem for ebook organization.

Also, you’ll avoid advertisements, which Amazon is now pushing to the homescreens even of kindles that were bought with the extra-cost no-ads option.

since podcasts are I think just RSS feeds of audio files (mp3 for those I’ve checked) the ads aren’t in any way marked in the stream. The only thing I’ve found is adjusting the skip buttons in antennapod so that skip fwd does 10 seconds, and back does 5; that seems to let me avoid listening to most of the ad; tap fwd until it’s back in material, then back once.

But I listen to a lot less podcasts; if I want hands- and eyes-free material I’m more likely to use TTS in my (text) RSS feed reader of choice, currently Feeder.

Kindle isn’t based on Android; it’s bare Linux with heavy DRM and a very limited ebook reader app on it. Whether the MacOS kindle app would help, I don’t know.

That looks like an app for playing audiobooks; I’ve used Voice Audiobook Player from f-droid for that.

If what you want is the recorded performance of someone reading a book, then yeah, librivox for legal audiobooks, and other commentors have other amswers that are on-topic. But DRM-free ebooks — text things, like epubs — can be read aloud by good ereader apps. I like Moon+ Reader Pro from Google Play, and Cool Reader from f-droid. For me, the emotionless robotic reading of TTS engines is more like a hands- and eyes-free way to enjoy the author’s words as written; I find listening to someone performing an audio reading of the book a different experience.

Before ebook reader apps learned about TTS I used to take my txt ebooks, feed them through flite (Festival Lite), then convert the resulting audio to ogg vorbis and load them on an iRiver PMP to play during long drives.