After a bit of searching I could not find a mod that displays the player's speed so I made my own.
It is in no way optimized... I did include the source file so anyone can see how this works and/or use the code if they want to.
This should work with any mod since it is entirely ACS-based with a few CVARs (all starting with "ws_")
It adds a small counter showing the movement speed of the player in map units/second.
There are options to disable each axis individually to for instance not carry vertical velocity or only vertical velocity.
Menu:

Spedometer (top center of screen):

Download: https://drive.google.com/file/d/1Ewz4uS ... sp=sharing