and is weird because I'm making a 2d game so I was expecting better performance than the GLES3.
Unfortunately, it's more complicated than that. The GLES3 renderer has an higher baseline cost, but is able to do some things more efficiently due to additional APIs that are simply not available in GLES2.
That said, the performance issue you're seeing seems to be incurred by this fix which was done to fix tilemap flickering on some hardware.