Improving vocabulary reading foreign language literature on ebook readers, how to export selected vocabulary into a spaced repetition app?

For improving my vocabulary I read favourite novels and short stories, preferredly in the original (target) language. When my level isn’t quite up to it, I read a translation (be that English or German), and then the original. With plot memory fresh, often the original meanings pop into place. Vocabulary that I need I do underline and look up, and since I do this with paper based books and dictionaries, I do need some space on a table for this. This method can be somewhat cumbersome while commuting using public transportation, but generally it has served me well over two decades now.

Years ago, with spaced repetition apps on a smartphone repeating less well-known vocab this learning method got an upgrade. Entering the words from paper notes into the app helps memorizing them as well, however, been wondering, can I upgrade this procedure too? Last time I checked, common ebook-readers had functions for selecting words and looking them up in dictionaries. While that is a useful feature in itself for some, all ecosystems failed to offer what I was missing then: a file export function.

I want to continue separate reading, looking things up, and repeating them as I did all these years. Not being able to export in effect cancels the device family status as a system seller; I see very little use in them if I can’t export.

For me, an ideal setup would be: load any given ebook in the target language into the reader. happy to load from any source. I’ll then be able to select vocab, and whenever I please export the list for further use. Optional: look things up on the ebook device and include the translation in the exported data. A plus: be able to select a suitable target format, csv, json, txt that my app can read and understand (here: AnkiDroid – I’d be happy to try and convert whatever the export data format is). Alternative: select word from the list, and directly “share to AnkiDroid” from reader device.

Which ebook reader, or mobile reader ecosystem, can do that for me? Any hints appreciated. Do you follow any comparable method for boosting vocabulary?

(In case it matters, the target language I particularly have on my mind here is Mandarin, which I’ve been learning for many years now, including by attending C1 level classes. Especially with simplified characters of 刘慈欣’s novels I need more practice in reading.)