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I checked out Volta's website and they state that only 2013-2015 MacBooks can undervolt. Later models cannot.

I've been trying myself to disable Turbo Boost on my 2017 MBP but no software has worked yet.
 
No, Apple block undervolting in the firmware. There is a lot of confusion over this with people thinking here undervolting with Volta, but all they're doing is lowering cpu wattage profile.
 
Im using the Turbo Boost Switcher app on mine and I believe it works since I get a bit of extra battery when needed
 
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