How about testing it on a prime like the 85 1.2L mkII, the 24 1.4L mkII, the sigma 35 1.4 art or the 50 1.4 art.
I think shooting with the 24-105 f4L leaves the door open for lack of image sharpness to be blamed on the IQ of the lens. Granted an APS-C sensor is not going to resolve sharpness or IQ as well as a…