Using the analogy of spoken languages ( a stretch I know ), I'd say there is a big difference in knowing enough to get by when traveling vs being fluent.

When a company is hiring, would they rather hire someone who can get by or a fluent speaker?

I think there is certainly a breath and depth balance to be had and I think you are correct in seeking more depth. A deep understanding of one language will allow you to more quickly gain depth in other languages.

And have fun!