What are the common techniques in dealing with too much data that’s still necessary

I'm working at a company where the operations team uses a dashboard to manage/monitor logistical operations. Not to make this problem specific to operations or logistics, I want to ask it in generic terms: This is what the dashboard looks like at a high level (blurring intentional for confidentiality):

The problem is that now the page is having way too much information, yet every time I ask someone if they need all the information on that page, they respond yes! every last bit of it.

My question is: can someone point me out to literature/terminology/case studies etc in how to deal with this situation? keep in mind I'm not a UX professional but I've worked in areas that overlaps with UX for most of my life.