so after that ?
Restart Opera. It will auto-magically recreate the necessary profile folder and populate it with fresh files containing default values and/or no personal data. That pretty much is the meaning of the term "reset".
But... I'd go the folder 'rename' route rather than the 'delete' route for your existing profile folder... that way, if all else fails, you can always at least get back to where you were before the renaming, by simply reversing the renaming process. If the initial folder renaming works entirely to fix whatever problems you're dealing with, then of course you can delete the old renamed folder. Whenever trying to fix things, it's always nice to write a ticket "back home" if you should need it.