No idea, aside from the steel chassis and copper/aluminum heatsinks. My company collects devices, sorts and disassembles them, and sells the scrap. Since we collect a lot of stuff that still works (like decommissioned corporate IT equipment), I work in the refurb division[0], so I don't have much insight into how much material can get broken down and recycled.
[0] https://www.ebay.com/str/evolutionecycling