@devicemart
Do you use Bulleyes OS or Buster OS on your RPi? The make file of the DXL-SDK needs some modifications if you use Bulleyes: please see this post
I have used the RPi4B and the CM-550 + XL-430s in previous projects, they worked together very well. See YouTube videos below:
The ROBOTIS e-manual shows some example codes for the DXL-SDK
If you are a beginner in this topic, you may also want to look at my book written for the Engineer System (Vol. 2) - which also used a Jetson Nano 2GB.
https://www.amazon.com/Projects-Guide-ROBOTIS-ENGINEER-2-ebook/dp/B09GN3VJ9P