My quick fix is to set an input length limit on the chat text. Testing out your input, it seems like around 70 is the limit for getting decent output from the LLM.
Email is just an odd case today since I was refunding an item. I usually want to focus on phrases everywhere, my yoga/pilates class, baseball team, sometimes TV, sometimes what I hear on a podcast, sometimes on a magazine, and get a detailed breakdown. It's not usually in formal, nor long.
I personally like both flash card directions because it allows me to practice how to write kanji for example instead of just recognizing, or in the context of phrases, it helps me practice active recalling rather than just passive recognition.
I tried so many apps, and was debating whether to build it myself. But it's impossible for me to build - no time and no creative juice left from my main job.