Old hardware is awesome to reuse most of the time but it’s not nearly as efficient as our hardware today.
It’s probably good to just properly recycle the old gear and spend $200 on a mini-PC from Amazon that has three times the power all while using less electricity.
I usually completely tear down old equipment into is raw materials, the best I can. It’s less likely to be shipped off to another country for uncontrolled destruction and I get more money back for the materials.