Hi Product-pressure,

When you get an animated joint rig into Cinema 4D it has keyframes.
Two suggestions Motion System and FBX
https://help.maxon.net/c4d/en-us/?_gl=11eppvug_gcl_auODUxNzQxMTg4LjE3MzIyMTg0NDU.#html/33015.html
https://help.maxon.net/c4d/en-us/?_gl=11eppvug*_gcl_au*ODUxNzQxMTg4LjE3MzIyMTg0NDU.#html/5310.html

Have the Null Body active.
Call up Main Menu> Animate. Add Animation Clip…
Make sure you have the Bake Expression checked.
When done, Command drag the Body Null to create a cop and delete the Motion Tag. This is my way; you might explore others, of course.
The Animation clip might need some cleanup and position adjustments.

As I do not answer from memory: here is my practical test with the current Cinema 4D release
Screenshot 2025-02-16 at 12.31.35 AM.jpg
The lower hierarchy is the copy.

Keep all results in the same joint hierarchy; I suggest always having a Null object as a parent.
Use the Motion/Animation System to create from each MoCap and Animation Clip, so you create a library that can be reused. Perhaps transfer the data to an existing Joint rig first. See Character Defenition for that:

Those clips can be shared (if they have the same hierarchy) even with others working on a larger project, for example.
Then it is like Film editing.

Here is a teaser where I use this system to create a hierarchy of elements. This will also work for joint-based setups, as this system was created for joint-based setups.
https://cineversity.maxon.net/en/series/animation_techniques_for_teams?tutorial=animation_techniques_for_teams_part_01_course

Other than that, a standard exchange format is FBX; older and newer formats should be explored for your needs if FBX is not wanted.
FBX (FilmBox, now Motion Builder) is based on an Industry standard app developed to clean up Motion capture data around three decades ago. Hence the standard.

If you have a small capature (<1MB as c4d), I'm happy to look into it and if needed provide some tips to improve it, etc.

Enjoy your weekend