I thought Markdown files being the source of truth was one of the desirable features of LogSeq.
I’m doing my own sync which is essentially to use git to sync with a remote on a server, so that I can work on either my laptop or my desktop system. I’m not using a mobile device at the moment and don’t have plans to (phone/tablet). This seems to work fine for me in the meantime. Since the data is in Markdown files, this works fine.
Admittedly, I am not a power user of LogSeq. Essentially, just keeping notes on things and linking the concepts as a 2nd brain.