Well, being able to get a player on the ground once a defender reaches him is another issue for Texas altogether.
A lot of the tackling issues stem from a failure of the player to bring his feet with him, that is, he launches himself at the tackle rather than running through it. Of course, over the last two weeks, the players in question have largely been CeeDee Lamb and Pooka Williams. Trying to fit up to either one, even when you're right in front of them, is a challenge for almost every player. They're just that good.
If Texas rushes 3, they're never getting to the QB. Eventually (not that long, really), a receiver will spring open - something that shouldn't occur with 8 defenders dropping. If they bring 5+, the time frame to the QB is shortened considerably, but they still almost never manage the sack. The Texas defenders are still athletic, and when told to run with a receiver can still usually manage it. However, Big 12 QBs are adept at dropping passes on a dime to defeat even tight 1 on 1 coverages.
Most teams that suffered the DB injuries Texas has would be playing walk-ons and undersized LBs. It's uncanny. However, the league isn't going to take that into account. We're still going to have to learn better defense.
As an aside, the KU QB needs to change running technique. He leads with his helmet battering ram style exactly how the NCAA has been ejecting players for over the last 3 years. I'm not seriously expecting the starting QB to be ejected for targeting, but he's going to seriously hurt himself or someone else if he doesn't learn to clean it up.
