Office 365 / 2019 Deployment Question

Can a local folder, instead of a UNC path, be specified for the UpdatePath in the xml or GPO? Here's an example from my XML I'm testing:

<Updates Enabled="TRUE" UpdatePath="C:\MSOfficeC2RCache" />

I don't want all users to update Office from the internet at once, and I need to roll out the updates in waves to users after properly testing. I am on an older build of SCCM that doesn't support managing Office 2019 C2R installations; I can only manage Office 365 ProPlus C2R with our current build of SCCM. (Do newer builds of SCCM currently support managing Office 2019 C2R?)

I know that I can point UpdatePath to "\\server\MSOfficeC2RCache" to control updates rollouts, but I also don't want each remote office to update directly from one central server across the WAN, but I'd rather roll out the updates to the local cache folder like I mentioned above, which will clear out the older version of updates so that the computers don't have more than the latest version of updates available in the local cache folder.