Ah, you used cheap labour from undocumented workers and it came back to bite you? There goes my sympathy.
As for the science, there are studies to suggest measures like shelter-in-place had an impact, and the fact that literally every form of mask reduces risk of transmission at least slightly has been established long before the nature of viral infections was understood. You could easily find these things online or through a university library, given how scientifically versed you are. But I suspect you’d cherry-pick the ones you like anyway, so why bother?