I'm definitely skeptical of anything congress investigates. When things turn political, then it becomes which side of the aisle thinks they can win and get a victory over the other. We've seen that in other areas of society that needed serious investigation, but it became one side fighting and the other protecting. It's the state of politics right now as no one can agree even on the things they should agree on.
Having said that, looking back at the steroid investigation into a baseball and we can see how they forced MLB to do something. No one was prosecuted, not even Palmeiro who committed perjury. I loved Palmeiro as a player, but he lied to congress and was vehement about it. But they forced MLB to take action, put in a policy, and it seemingly cleaned up some of that. We can debate the effectiveness of it, but they did finally put in a policy and people are still being punished for violating it. Perhaps that is what will come out of this. They will force the NFL to actually do something about Snyder.