why not just say 'millions'
"Our next iteration of this scheduler aims to scale to millions of GPUs"
I treat it as more akin to the (slightly more-awkward) "single-digit millions" whereas "millions" could go over. It's just a SV-ism. I usually find it pretty easy to disambiguate and I confuse it as little as I do the same / in dy/dx vs. 1/2. Notational overload is pretty normal in human communication, I think.