fwiw the h1-b workers I encountered in bigtech were totally on-par with their US citizen equivalents in both coding and english communication. many teams were about 50/50 in my office (SF, non-HQ).
my current talent/placement company works mostly with AI startups who are usually too early to support visa requirements [0]. being able to support the lead-time and planning for international applicants is a huge advantage later stage companies have in terms of being able to scoop up talent at reasonable prices. big loss for the local ecosystems if these jobs move across the border imo.