Would be nice if you posted a screenshot of your map so we can see how much you discovered.
I started several worlds where I finished the game and I never had bad luck with the second boss.
Really curious how much of a "bad luck" situation this is.
Not saying this isn't true, but the first time I played the game I spent a huge amount of time in the beginning discovering things between first and second boss and it was really enjoyable.
But 72 hours? is that the real time spent up to finding the second boss? That is insane, I spent that much on the entire game up to last boss in my first attempt!