@kmielczarczyk This no display issue when requireInteraction = true is now also an issue on Chrome on macOS 10.15 too. However this original Opera issue was a problem even for macOS 10.14.
See this Chromium issue for more details on the macOS 10.15 issue.
@kmielczarczyk Maybe Opera can implement the same work around? Or will Opera just get this downstream automatically in the future?
As far as those who use the OneSignal service to send Web Push we have worked around this by disabling requireInteraction when running Opera on macOS 10.14+.