That particular cover cost almost $1400. It was custom built with a hole for the power pole, and modified to fit without removing the trolling motor. They also lined the inside, where the cover came in contact with the trolling motor, with a rubber material to reduce wear and/or puncture from a...
Call T-Tops and speak to their sales staff. I had them make one for a 2019 Parker 21se. If they have the dimensions on file for a 21 dv they should be able to turn one out in a couple weeks.
https://ttopcovers.com/