I also want to record Phone Call info from Flow with From/To. The Dynamics 365 Connector doesn't show ActivityParty as an option, but typing it directly works:

Although this thread is about PowerApps, others seemed to be searching for this solution, as I was when I came here.
EDIT: this DOES NOT work :_(
The 'Create' method does not support entities of type 'activityparty'.
Same error when trying through the CDS connector, too.