Hey @Panuchka. Pretty new here so take my advise with grain of salt but I would like to suggest alternative approach.
For example, have you looked at ArcRotateCamera - it gives you manual control over rotation around focus point. Might be even more fun for your use case. 
You could just set it exactly how you want it and then in your update step use move the camera along with your target updating position with movement delta and using camera.setTarget(mesh) (docs) to refocus it on the target.
Check this out. ArcRotate (without attaching controls) instead of follow that does what you need I believe.
https://www.babylonjs-playground.com/#4TS4WS