That's a valid point, definitely. I don't miss synchronization on my iPhone actually, but on the iPad Opera appears rather rudimentary. As I don't use the IPad that much any more, it's ok for me, but I can understand your point.
If you want to have a more Opera like experience on desktop and iPad you may like to install Vivaldi browser, which you can customize to look like Opera with sidebar, speed dials and some handy features, only missing AI integration as with Aria. The synchronization feature is decent and even better as that in Firefox.