[1] Get a "server as they should be", https://oxide.computer (no affiliation)
But then, when uncontrolled inefficiencies need to gobble up more hardware, you would have to buy, install, network, maintain, and understand this new hardware.
Real inefficiencies do, but then you will have the more detailed data the GP is talking about.
You don't need to make a large datacenter, or to migrate everything at once. Find some low-risk services, get some consultant help you improve some room on your premises (you'll need to care about security, electricity and cooling), get a pair of network contracts and one hack of servers (or maybe even 4 servers), and move those services. Favor things that are used internally.
If you are looking for 7 figures of savings just by picking the easy fruit, you will almost certainly get positive ROI on that. Just do not move critical services if you don't know what you are doing.