Unfortunately, Grothendieck, Galois and as far as I know, Bourbaki is not fully translated. And unless someone actually spends many years doing it, a lot of it never will be.

I also think Russian is useful, especially to read some old texts from the cold war era. But a lot of the books are translated (but not the papers). Kolmogorov's books and probably quite a few others were translated not very long after they were written.

But, to be honest, I think knowing French and Russian is more of a personal pursuit than a necessity to access the mathematiacs. Galois wrote down very little and his memoirs (written by someone else) should be the interesting historically. Grothendieck should also be interesting, especially to see his unrelenting commitment to translate everything to category theory. However, for almost any topic, somewhere, in English, there would be a good source. Bourbaki was never really "completed" and I am not sure whether it's useful to read those texts (rather than the stuff that was inspired by them).

I can recommend Lawvere's books, especially Conceptual Mathematics since it's even accessible for high school students. My main interest is in category theory and set theory, so it may well not be what you are interested in.

I've also seen really useful stuff in the internet era, like Category Theory for Programmers by Bartosz Milewski.