I've been looking for something similar too. I've no experience with either, but currently eyeing Seafile https://www.seafile.com/en/home/ https://www.seafile.c

I've been looking for something similar too. I've no experience with either, but currently eyeing Seafile https://www.seafile.com/en/home/ https://www.seafile.com/en/home/ or OwnCloud https://owncloud.com https://owncloud.com. OwnCloud seems perfect, but quite pricey for a cloud-provided instance. Seafile looks good, but there's no cloud provided option unfortunately (i'd rather not self-host).