Iâm not saying it shouldnât be addressed, but unfortunately it isnât that easy, because as @wwe already mentioned, Linux doesnât have a standardized API for this like macOS and Windows do.
Thereâs a fairly long discussion on GitHub that provides some insight into the challenges involved. Feel free to add a comment there if you have any concrete suggestions on how this could be implemented: VFS on Linux · Issue #3668 · nextcloud/desktop · GitHub
However, there is what I would call a âlightâ version of Virtual Files available on Linux, which works by using placeholder files. As far as I know, it is still considered experimental. See this post for information on how to enable it: Virtual Files on Ubuntu Desktop - #4 by bb77
Otherwise, as already mentioned by others, WebDAV is probably your best option if storage space is limited on the client devices. Alternatively, you could use a combination of WebDAV and selectively synced folders via the desktop client. That way, you can save storage space while still keeping certain files available offline.