Honestly, this question is really revealing, because it's the lower-paid SWE jobs that are probably not Bay Area or NYC, which are precisely the places where lower* English fluency is most likely to be tolerated or even the majority.

I was the only person on my 5-person team with 'Business English' at my first BA startup, so I got the job of writing all external-routing communications.

When I worked remote for a Midwest company years later, it was very clear that anything but perfect English was disqualifying in the eyes of a lot of (Midwest white male) management there.