I looked around these forums a bit and found that Vivaldi does not offer a sync service. That's cool (for now), but I wonder if there are any alternatives. Is there a way to export the goodies? Perhaps I could upload that export to my cloud somewhere and download them for import on another PC I use. Lastly, would a sync service really consume a large amount of bandwidth and server storage space, considering that the date is not large?
You can sync some relevant files like the bookmarks using rsync the powertoys and alike
You can also place the whole user on a remote drive mounted locally by something like clouddrive.
if you mind to sync just with a mobile I think there are many solutions.
I've tested the Dolphin extension and it worked flawlessly