It's FIXED!! It appears my issue has been resolved without having to send the drone in for repairs.
I had contacted DJI on Sunday and heard back yesterday. They recommended the following and I've now flown two 15 minute flights in similar temps, winds, and bright sun with no wavy lines / jello. Here's what they had me do.
1. Upgrade to latest firmware (mine was already up to date).
2. IMU calibration
3. Gimbal calibration
4. Camera reset (within the camera settings, click on cog wheel, or wrench depending on version, and tap "camera reset").
That's it! That last one erases all your camera configs so, i flew once with the default settings and again after i changed to my preferred resolution, color profile, etc. I ran into a small issue where it wouldn't let me select 4k video... it was no longer an option, but a reboot brought it back.
Hopefully this works for others as well. I'll keep flying and will update everyone if anything changes.
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