Hm, i would need to test this myself, but taking the Z value for up and down movement and the X and Y for the should work.
Try to use the Z alone for the UP and DOWN thing and make a new vector out of the X and Y value. Set the Z value of this new vector to 0 and try to get the length (like you would do to get the speed from the normal velocity).
This SHOULD give your the speed of the character for X and Y…
If this is not working, then i would need to have a look at it myself, but i’m currently totaly stuck in learning for exams. 