This. All of this. And I thank you for putting it into words and doing it so well.
It can be far too easy to demonize someone when the perspective used to approach them doesn't leave room for empathy, reason, and understanding.
The part of about Lucius being hard on Luke matches pitch-perfect with how Luke and Lucius's relationship was generally portrayed during his solo. Basically, Luke enjoyed his "me time" being a globe-trotting MMA fighter to go along with his prestigious degrees and acumen in his field as a mechanical engineer, in spite of the pressure to live up to Lucius's expectations as the heir apparent, so to speak. This story simply adds context to the why. Thanks to Second Son's additions, we now know that it wasn't just a generic "you gotta do everything perfect" Black Education Dad narrative. It was deeper. We now know that Lucius's pressuring of Luke was due to the trauma from the whole situation with Jace. And with this context, it makes all the sense in the world that Luke would hold a grudge against Jace. That type of pressure-fueled resentment isn't something you can just brush aside. And like you say, the stress and anxiety just adds when you factor Luke's double-life as Batwing.