Duolingo actually used to have a full flashcard app before the shut it down iirc, though I don't remember exactly how customizeable it was. My process is usually study input (TV show, book, etc), break down grammar and look up unknown words, make flashcards of said words, then review the flashcards and input. Plus going through textbooks, and grammar resources. As well as lots and lots of input in general, usually without worrying abt mining or it's smth I can't mine easily. With as much output as I can handle lol. AI/LLMs aren't accurate enough imo in my NL, so I wouldn't use them for study material personally. At most for beginner speaking, like how you might put a sentence into smth like Google translate to see if you butchered it. Same with TTS if you have other options. They're better suited for things you can fact check/see errors in yourself imo, as they're supposed to be more casual "fast and loose" type aggregates vs highly nuanced and accurate.
LLMs thrive in generating simple sentences. This way you can give them the vocabulary bank and ask them to generate a simple sentence that uses only vocab from this bank, then you can copy this sentence into the anki writing exercise together with a translation and have the exercise in which you will use the new phrase in context. But generally I agree that when it comes to grammar or more theoretical considerations, then LLMs are not to be fully trusted