Best way for external WebDAV Access


I would like to be able to safely access MyCloud remotely. I understood that this should be possible using WebDAV. I already managed to set this up in the local network. But how can I safely access the NAS externally? I read about DynDNS, is it save? Also, with a FritzBox router, It seems to be possible to set up a VPN connection to the network, would this be better? What are the alternatives? Thanks for your help