That’s not really how it works. A goal negates a delayed penalty whether you get the extra man on or not.
It’s an interesting thought though. And really I would think there’s a sizeable amount of people that think it’s stupid to have the goal negate the delayed penalty as is. As you noted, it’s not like you actually got the man advantage.
Does it negate a major or just a minor? I thought only a minor was negated.