If you don't have ten years of experience with at least five very-distinct languages (i.e., C & C++ only count once, & Java and C# only count once), you're not really a developer yet -- just an apprentice.

Sorry to say, there's no way to cut the gordian knot there: you're going to have to wait until you gain the necessary experience before you're a benefit rather than a liability.

If it's any consolation, most people with entry level / junior software engineer jobs are in the same boat, & there are whole companies that are essentially doomed because of a monoculture of people who haven't yet reached minimum competence. If you're surrounded by peers that know twelve languages & have been working as a dev for twenty years, then you're in a much better place than most of your cohort.