Here’s a sample 360 video from the Qoocam 8K (reviewed here) with the Dive Case, shot by Laura James, a professional 360 videographer who specializes in underwater 360 videos, among other genres:
The stitching looks pretty smooth as you can see from the uninterrupted zenith. Please note that the circular lines in the video are not a stitching issue. They are reflections of the gold band around the Qoocam 8K lens. The Dive Case does include a black sticker for covering the gold band.
The Dive Case is available direct from KandaoVR.com and costs $129.