Somewhat fixed the elegant 3 Axis Camera Gimbal originally built by @BaconAircraft.

Roll/pitch/yaw to test.
VTOL to zoom Camera1.

The key was the added fuel tank block with negative mass. It is on the top of the camera shell. Because if something got positively weighted, then it could't avoid the influence of its inertia. That explains the swing of the view. The lift force was added to neutralize the inertia effect. But sadly through my tests, you can't totally rely on lift only. There still need something weighted enough, or there would be an explosion after you press the Play button.

The other known side-effect is the third-person view would be influenced by the negative mass xml-modding. Since anything I touched in the camera would cause it's explosion, I didn't modify the inner structure of the original build. Further improvements to help it getting better are welcome : )

Learned how to make negative mass block from @spefyjerbf's build. Many thanks to him! I highly recommend all of you guys reading this now go to upvote his great work! And besides this one he also has many other great builds worth your upvotes!

https://www.simpleplanes.com/a/fc9c4X/Closed-Challenge-Break-the-physics-Plus-some-subs-for-the-challenge

Of course, don't forget @BaconAircraft! I quite like many of his builds! I'm the follower to both of them!

https://www.simpleplanes.com/u/BaconAircraft/Posts

Have fun!