Hi mate!
I've implemented a solution to this by letting users use Custom APIs as suggested by another user. It's available in the 0.4.9_beta version.
Please let me know if you do try it and if you have any suggestions for it! I can confirm it works when I self-hosted LibreTranslate, which uses Argos Translate (..which in turn uses Ctranslate2).
As always, many thanks for all your suggestions, testing and feedback! 🎖️