It sounds like a good approach to me. I've only fairly recently started to try and import content from ebooks. It's a bit of a problem when trying to import from a kindle ebook at least so far for me. I think the file would need to be converted to mobi or other format, but on the latest iteration of the kindle desktop reader apparently they are using a new DRM that hasn't been cracked yet. So I've been copying chapters. I've noticed on at least one e-book though there is a limit by the publisher to how much you can copy. So I've recently started grabbing content from that book with OCR software. Kind of a pain, but it works.
If you're content is in epub, mobi, pdf or other format it looks like it should be a lot easier.
dw.com has a lot of news videos on youtube...
you can import youtube videos and it will pull in the subtitles (german). That might be another approach. Only issue I've found with that is in the past I've sometimes ended up with no punctuation. On one I tried today though I got the punctuation so maybe they fixed something.
So really any youtube videos that have the german subtitles should work too if you can find interesting content from there.
has simpliefied news articles and slow audio to go with them. That may be too easy for you?
I was able to convert and upload (to private lessons) both my Kindle and Audible content, and have started working through the Dresden Files by Jim Butcher. I find them both fun, and particularly useful for a language learner as they are written in 1st Person.August 15 at 15:55