Struggling to successfully print top covers.

I'm printing on a P1S with a cold plate and even added the suggested brim ears, but I still can't print covers taller than about 4 inches without failure. I'm getting a random layer shift, and then eventually it seems like maybe the print head is knocking it over. The initial layer is so thin with the curved ends that I'm not sure how to succeed in the vertical setup. Anyone have suggestions for how to adjust the settings? I'm not skilled at editing yet, so other than figuring out another kind of support or trying to print it flat I'm out of options.