did you try the lower resolution? is it better, how about tying the command "gst-launch-1.0 v4l2src ! video/x-raw,width=1920,height=1080 ! waylandsink"?
you can try to use v4l2 to capture one picture to check if the performance, if this is good, it seems this is related to your display side, this isn't imx93 issue, imx93 HW can support 1080p@30