Exactly.
Since you're using the 5.6 kernel and the modules that come with it, all the kernel and driver updates released since 5.6 are not active on your system now. If you're using any add-on drivers from e.g. your server hardware manufacturer, use the "modinfo <module name>" command to verify the version number of the driver module that is actually running, and consult the appropriate driver release notes.
For a detailed list of kernel changes since 5.6, go to:
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/
and find the documents "5.7 Technical Notes", "5.8 Technical Notes" and "5.9 Technical Notes". On each document, read the "kernel" subchapter in the "Package Updates" chapter.
For a more condensed list, check the Release Notes for 5.7, 5.8 and 5.9 for any kernel- and driver-related updates. The release notes can be found on the same page as the Technical Notes.