> some content can not be translated, or the translation can not be displayed

Translations are always a guess and best effort. We could potentially add features to mitigate the issue, such as a setting to define your own language prediction minimum confidence level (currently 50%), or allow you to force translation from the language of choice.

> when Damus is relaunched, it will re-request the translation of the previously translated content

We also don’t cache the original notes when Damus is relaunched. If we want to go down the route of caching translations, we probably also want to cache the original notes. I’ll ask the Damus contributors what they think about that.