I got a notice of Strongsync, a new integrated sync/Spotlight app from the makers of Expandrive.
From their marketing, not only is this a big deal but also it is integrated with Big Sur as a “File Provider” - see Apple Developer Documentation
See also:
https://www.expandrive.com/strongsync/
I know DevonTech has long advocated strongly against locating DT3 database files in any cloud location. I suspect that advice might hold with Strongsync as well. However, does it change things at all that this app apparently is integrated into Big Sur via a software mechanism explicitly approved by Apple for this purpose?