f13a-6c3a I have no problem with offline voice typing while both Gboard and Speech Services by Google (SSbG) not having Network permission.
Same here with GBoard the time I tried it. I don't understand why others are having issues with GBoard, like in this thread. At the end of the day, who knows how these Google apps work.
I just tried the offline Google Translate thing. I get the same results as you.
I personally use DeepL. It also requires network access, but at least it's not a Google app so it doesn't bother me. It's not as good as Google Translate, but it still works well enough for me.