You need to fix the underlying issue, i.e., the backend returning 503. It sounds easy to have Discourse retry the same translation over and over, but you need to keep in mind that each request to an LLM incurs a token cost, and we need to be conservative on our side to not use up those tokens. Once you have fixed the LLM issue, you can manually schedule a topic for translation and see if it gets resolved.
Please adjust your expectations. You’re using free software and we’re helping you as much as we can.