TL;DR: download the zip file from here (search rehid_w_virtual_sliders on github) and unzip it to your sd card root. Make sure you have FIRM patching in Luma3ds settings. Use START+L/R to adjust volume, SELECT+L/R to adjust 3D. Does not work under DS (+ GBA?) mode.
You don't need rehidhelper...
Caller -"Everytime I start a Pc game on my S24, playing on a external monitor, someone calls or texts me, n it kicks me out of the game." Customer Support - Click (hangs up)
I found it funny cause many many years ago, had a roommate in college that did this same dumbass branding of the school logo, but it didn't look anything like it after it healed. Just looked like a birthmark.