Is this the unedited 4K video from the SD card? Looking at it, I think that is more "jello effect" than anything else...
I found that artifact in my early videos as well. If that is the case, the first thing you need to do is to learn how to
balance your props. You can get a good prop balancer for $25... the Du Bro Tru-Spin works well for me.
Looks like jello. Usually caused by props out of balance or gimbal defect or maybe a gimbal dampener has come loose. Have you had a crash or rough landing?
1. check dampeners
2. swap props with spares
3. run motors without props and feel for vibrations'
4. feel the belly of the H while hovering for vibrations
5. recalibrate gimbal/camera
6. power up gimbal with rotors turned off, listen and feel for vibrations
"Jello" in H video is generally caused by an anti vibration damper that has separated from the gimbal mount. Remove the gimbal from the H, lift the top cover from the gimbal, and check the dampers.
"Flickering" is due to propeller blades casting shadows on the lens in some sun/lens relationship positions.
Video playback on view screens that do not support higher resolution video can also induce frame rate "stuttering". If you play HD video the viewing device must have equal or higher resolution capability. Computers must be relatively fast and have a graphics card capable of dealing with high resolution video.
There are quite a few things we can do wrong or not understand to make for a less than ideal video. It takes a little time to learn what all of them are.