How do I keep animation speed over multiple keyframes? So, let's say we have a "speed" of 6.918m per 20 frames.

6.918 is the movement distance in the top left of the GIF below - the movement occurs over 20 frames - hence, 6.918 metres per 20 frames.



Next, I would like to keyframe the object to continue moving 3 frames later, at the same speed.



For simplicity, let's presume I am using linear interpolation. To keep movement speed consistent, I would need to move the object by ((6.918 ÷ 20) × 3) =1.077 metres.

However:


I would like to be able to do this without using a calculator every time.
I would like to be able to make the object travel in a circle, figure of eight, or any hand-keyframed  movement I would like on any axis, at the same speed.
I would like to also be able to do this with rotations.


Therefore, my question is: How can I set a 'speed' for my object so that I am able to move and rotate it at a consistent rate across multiple keyframes?

For extra clarification, I would like to achieve this:



But without using a calculator, and moving the box on all 3 axis at once (notice in the gif I can only move the box on one axis at a time) by setting keyframes. Also to do something similar but with rotations.
Create a path using "poli" type curve
parent the cube to the curve
use path animation and choose the number of frame based on the path total length to get the desired speed


Note: check the Follow option so that the cube rotates along the curve