Hi
When you are learning a new language, you need to practice different skills: reading, listening, speaking, writing. I find writing to be the hardest activity, not least because I have to look up words in the dictionary all the time, and that is a frustrating context switch.
Here is an experimental CodeMirror-based editor, that lets you look up translations inline. Type @ followed by the English word, and get a list of possible translations, and select the translation to apply it.
Online demo: https://foreign-dispatch-autocomplete.netlify.app/
I think it's quite original to have the starting point of "I'm almost good enough to write on my own" in stead of starting in the usual spot of full-auto translation pipe dream.
I occasionally use deepl to write messages in languages which I'm rusty, but the-back-and-forth between editing my final output and selecting suggestions in not smooth.