James Rankin wrote a blog article on configuring Storage Sense for OneDrive, FWIW. I have my environment (CVAD 1912 LTSR CU3, W10 20H2) configured the same way, and the last time I checked, it appeared to work. A scheduled task actually kicks off the Storage Sense function. Also, are you shrinking your containers on a routine basis? In my environment, the initial OneDrive run with Files On Demand enabled still bloating my own container to 11GB in size. I run Jim Moyle's FSL shrink script nightly, which brought it back down to 800MB or so. That has made the biggest difference in my environment for more than just OneDrive.
FSLogix, OneDrive for Business Cache, Non-Persistent VDI Issues
I'm currently trying to figure out how to keep our FSLogix OneDrive cache folder in a clean state (i.e. use Storage Sense on our non-persistent VDI's to automatically "dehydrate" any OneDrive cached files that haven't been used in 14 days). So far Storage Sense does not appear to be "dehydrating" any OneDrive cached files that haven't been accessed in that time frame (for testing I set it to 1 day old OneDrive cached files to be removed), and there also appears to be no way to trigger Storage Sense to run at an exact time. I have set all the relevant group polices and running Storage Sense manually appears to be "dehydrating" the files, just not automatically.
What are others doing to try and keep their FSLogix Office container VHDX's as small as possible?