@aral All you need is to send me your API key for DeepL or LibreTranslate and I can add it to your env variables.
Not the same as having it in the Mastodon administration section but you can have translation even if you are using my service.
Also, I can add an option on Masto.host web interface to change automate this process. For now it's just manual but some instances have already sent me their API keys and it's working great.