I'm surprised that Firefox Translate includes Bulgarian but not Russian in its list of available languages. It seems to me that the latter language is far more important.
@drjlevi6that's curious, en->ru should not be available (unless you enabled some hidden configs to use pre-release models). Anyway, it should be available soon for everybody (and it will be better than the current one).
Quick update - support for Russian translations is available in Firefox Nightly. We are still working to get it ready for release in Firefox and will update you all here when that happens. Thanks for the ongoing feedback and patience 🙌