If ‘contacts’ , ‘calendar’ & ‘sync’ are not your main needs, perhaps you may wish to consider to build a KVM web server where to host and run a full featured ‘Nexcloud 13’ version but by just ignoring the build in one in MiaB as there is no option to skip its installation ( at least not yet 
) . The MNX.io - Storage Instance with 500Gb ( 7 USD/ mo) is a good offer from where to start with.
BTW, building your web server with Serverpilot.io is a breath … :