My guess is that those 3 are big ratings draws no matter when they play so you might as well put them against stronger tv competition, while Nebraska can pop a really nice rating Friday assuming... Friday Night SmackDown doesn't have a hot pro wrasslin angle.
I think they want to avoid Fridays being the Rutgers-Purdue-MN-Illinois show. That's why on the Friday schedule you see: Oregon, Washington (x2), Nebraska, USC, Michigan State, Cockeye, etc. Taters are way too concerned with what PSU/OSU/UM are doing. They really need to chill out.
My prediction: I think some of these Friday games might get 3-4m+ viewers this year. That will change a lot of opinions about the Friday night time slot. National TV FOX with the schedule all to yourself in Friday is a HELL of a lot better than BTN at 11am vs 30 other games. This is a no-brainer for me.
***Remember, our biggest home game of the last few years (vs Michigan 2021) was not seen by a lot of mainstream CFB fans bc they were watching #2 Alabama at Texas A&M (41-38 A&M victory). The SEC game was in the same time slot on CBS and pulled a way bigger TV rating. And if you followed Twitter that night, 75% of CFB posts were about the Bama/A&M game. No one was watching NU/MICH. Point is that having a national TV time slot all to yourself is a massive deal.