Can confirm that there is no performance gain in Dolphin on Windows 10, at least not in OpenGL. I am very intimately familiar with the exact fps my system is capable of spitting out under OGL in Metroid Prime. There are exact moments where I memorized my framerate, and it didn't change.
CPU: AMD 7950x3D GPU: RTX 4090 Founder's Edition Mobo: ASUS B650E-F STRIX RAM: G-Skill 64GB DDR5 6000Mhz PSU: EVGA Supernova 850w Titanium Case: Coolermaster HAF X O/S: Windows 11 22H2 Pro x64