@refazeshot1 check out this: https://www.libretro.com/index.php/changing-behavior-of-gl-and-glcore-video-drivers/
“gl” is an OpenGL 2.0+ driver, when used with a version above 3.0 it’s called OpenGL Compatibility and can support up to OpenGL 4.6, but some GPU drivers don’t have that OpenGL Compatibility mode.
it supports GLES from 1.0 to 3.x. pi4 is gles 3.1 in current retropie.
“glcore” is an OpenGL 3.1+ driver, it’s also called OpenGL Core, it supports up to OpenGL 4.6.
i think the mesa driver in current retropie supports open gl 2.1 on the pi4. so glcore is pointless/may cause issues.