Ruining this command from Terminal blocks the AutoUpdate.
defaults write com.operasoftware.Opera OPDisableAutoUpdate true
About why the latest update broke the start up, I don't know.
You should try with a clean install or wait for the next update (despite that it's not assuring to fix the problem.)
For the clean profile, look at here.
Windows 10 (x64) | Anniversary Update
Opera Stable · Beta · Developer
Opera Test profile | Opera Back up Linux · Mac · Win