@burnout426
Your link to "block Opera's update servers" redirect to a procedure that's only for Windows.
On MacOS (for this versions it was MacOS and not macOS as currently is) you can disable autoupdate for Opera stable by typing this into a terminal:
defaults write com.operasoftware.Opera OPDisableAutoUpdate true
If it worked, Opera will tell you "Update checker is disabled" when you go to Opera -> About Opera.
You must apply this Opera automatic update blocker BEFORE running Opera for the first time. Don't forget this very important step!