Just rolled out a small lab today, and I'm using volume-serialized Office 2019.
Since making default user profiles are pretty much not feasible anymore since Mojave, I've been searching around for configuration profiles or plists to deploy that suppress the first run dialog for Office 2019 apps, and also the Data Notice popup from Microsoft I found a config profile AutoUpdate.
I found the following for MAU: https://github.com/rtrouton/profiles/tree/master/DisableMAURequiredDataNotice
However, everything I'm coming across for suppressing first-runs is written for Office 2016.
Anyone successfully stopped Office 2019 first-runs yet with Jamf?