I will try all your ideas and tell when I found one fixing the problem ;D
Thx for all the help.

Yeah, it’s the individual object matrices which become denormalized. If you perform all the calculations and rendering in camera space instead of world space (by moving everything so the camera is at the origin before rendering the frame, then reverting all that after rendering), you already get a noticeably lower amount of shaking for the exact same inputs. The rest of the shaking is probably caused by the positions themselves becoming inaccurate.

Unfortunately, I don’t have the ability to do that space transformation for everything (specifically, it breaks ALEs and I believe stars), so it’s not currently viable.