Currently we have an experimental VFS feature on all platforms that is using some suffix appended to files when they are virtual empty placeholders. https://github.com/nextcloud/desktop/issues/3668
Yeah, no thanks. It’s a very hacky work-around and breaks the moment you use an application that tries to access the files directly.
My (self-hosted) cloud storage is larger than the disk drive on my laptop. On demand sync is important to me. I really, really hope Linux will catch up to Windows in that regard.