Share Point (2019) On-Premise & Share Point Office 365 - Synchronization
Being able to host an on-premise Share Point Server (2019), that synchronizes real time bidirectionally with Office 365 Share Point. (To Improve Performance / Business continuity)
Also, it would need to have the options of cloning the sites and other pages from Share Point Office 365 to the on-premise Share Point Server (2019). With offering as much full functionality as possible.