I use the UR824 with Cubase 11 Elements and can get the rack intergration. I don’t know what OS you are using but if it’s Windows make sure you are on Windows 10. On Windows 7 it doesn’t work properly. I initialy had this issue when they dropped Windows 7 support at Cubase 10.5. You would need to use Cubase 10 which is probably the last time the feature worked if you are determined to keep using Windows 7.
Here’s my thread about it from mid 2020:
If you’re on a Mac I don’t know what the issue might be.