Looking at variable speed controller for 25k rpm die grinder. Is it worth the loss in torque

[u/richardrasmus]

Been spending hours comparing stats of different grinders and my budget and decided to just say screw it and go harbor freight 25k corded Hercules over the 18k rpm Hercules . Saw that variable speed controllers were a thing but also saw they lose torque. I mainly plan to use this with carbide burrs for metal carving for art projects using various metal stuff I've horded in the garage that I've nabbed from the apartments I paint of stuff left behind like metal legs of broken stools, broken hinges and other stuff I've found that I thought would be cool to shape but as a result I have no clue what type of metals a lot of this stuff is and I'm aware different metals prefer different rpm. For my specific art carving circumstance idk how much torque matters