I wasn't able to watch the game because of a work thing, but watching the extended highlights, Allar had a terrible game. Leonard was never going to have a good (throwing) game. Freeman appeared to make good adjustments at half time, but Penn State weathered it, despite a big momentum swing in the 3rd quarter. At the end of the day, unsurprisingly, little things made the difference. PSU should have had a touchdown on that first FG drive. Receiver drops the ball. ND was lucky to recover the fumble at the end of the first half, leading to a FG. PSU DB falls down, giving up the tying TD in the 4th quarter. Then Allar makes his third--and worst--mistake throwing the ball to the other team.
I also agree that ND doesn't look like a team that will push OSU all that hard, but maybe they have a better secondary than OSU is used to facing? And they can grind the clock with their running game, and can put pressure on OSU's thinned out offensive line? They do appear to have a very good defense.
As for Texas vs. ND? I just don't know Texas well enough to have an opinion.