Much like PCloud (which has recently been added), IceDrive (WebDAV ready), Koofr (WebDAV ready) and Internxt (WebDAV coming) are major contenders and would be highly desirable as the backend cloud storage systems for the Updraft WordPress plugin.
IceDrive is a major provider of massive storage that actually works well and although slightly behind PCloud, it is actually a solid solution for cloud storage.
Koofr is a solid choice (although on the expensive side) for their sharing capabilities and massive storage plans.
Degoo can offer a massive storage volume but has no mobile apps or WebDAV plans in their future. It would be good to allow users to backup their websites to their massive Degoo 10 TB volume.
These suggestions are being made as the WebDAV interface is dysfunctional. and two of three of the storage solutions above have no WebDAV capability.
I have submitted a ticket for a dysfunctional WebDAV in the past and the support group wore me out despite the solid troubleshooting and write-up provided, and despite following all suggestions and instructions. I tried it with PCloud, IceDrive, and Koofr and they all failed the same way… Backup files made on the back-end volumes are 1 to 2K each where they should be MUCH larger, and restores will never work… Common denominator is the Plugin and GoDaddy, but my gut tells me it is not GoDaddy because it actually opens the remote volume on every storage solution complete with file names, but does not put the entire chunk in there, regardless of the chunk size (and many other things tried) as suggested by support. Results are 7 to 8 useless files on the remote storage volume regardless of the storage solution used.
If we had the native storage interfaces for these storage solutions, we would all benefit, they sell more storage, we get to use existing solid solutions, and Updraft will be a natural pick for your ability to interface with various renounced cloud storage solutions that offer massive and/or expandable volumes.