The default Linux image on AWS (Amazon Linux) is RPM-based; but the default image on Google Cloud currently appears to be Debian "bullseye" (the April 2023 release) with an option for "bookworm" (brand new this month). I'm not sure about Microsoft Azure but their docs suggest a Debian default as well.
So that's one impression. Knowing both dpkg/apt and rpm will serve you well.
Major tech companies have their own internal distributions in their production datacenters, which focus much more on their specific needs. Any major tech company using Linux in datacenters will have an engineering team specifically building what they need.