It comes in about 0.2-0.3 people per MW, but as the size rises the number of people per MW reduces.

So, a 100MW DC will have about 20-30 people and a 1GW campus will be 200-300 people.

Those numbers can be boosted if the site has a significant non-operational support staff such as security and cleaning. But a significant part of security us heavily automated, to the point where when Meta had a major network failure they couldn't get on-call support staff into the facilities to fix the issue because the security doors were linked to the main network.