I've always enjoyed Opera, have used it for 10+ years, but this may be the last straw. Not having access to my bookmarks in iOS is a real dealbreaker.
Best posts made by botisdale
RE: iPhone iOS Opera BookmarksOpera Browser
RE: Backward and forward buttons on Logitech Mouse not working with OperaOpera for Mac
The only workaround I found successful is to move the mouse cursor to the far edge of the screen (to get a window resize cursor) and only then backward and forward buttons are working.
That's my experience too. It's the only workaround I've found. I really wish they'd fix this because I do prefer Opera to Chrome for many reasons.
Environment: MacOS High Sierra 10.13.6 with a non-Logitech mouse.