The "they knew nothing during their first time around" argument is not a helpful one, because any number of exotic things could have happened during their first time around already. Nothing necessitates an "uneventful" original run where the only event is the ship crashing into a time loop, or makes this more or less likely than an "eventful" run where all sorts of things happen and just one of those is responsible for the loop.
But it is THE MOST HELPFUL argument! They are stuck in a loop that is repeating itself over and over again, the only thing that changes is the actions of the crew. So if any "exotic thing" had happened on their initial journey to the first collision it would also have happened in all of the subsequent loops! The first time is only different in that the crew has no memory of past loops, since there were
no past loops. So, no memory of previous loops means no discussion in the conference lounge whioch means NO suggestion to change course. So changing course MUST avoid the collision.
It IS that simple!