Rhaenyra's children were all born out of love and desire. She had three with Harwin whom she loved, and more with Daemon, whom she also loves.
Alicent's children were out of obligation and duty. Every time we saw her as a young mother, she looked bewildered and burdened, bouncing crying babies while she looked off in the distance.
Rhaenyra can look at every one of her children and remember the face of their father and reminisce about the passionate lovemaking that led to the conception. Alicent looks at her kids and remembers being called into the chamber of an old man leaking puss, and getting pounded while rats ran across the ceiling. I think this plays a part in why Rhaenyra is so loving with her kids, and while Alicent tries to be patient and loving with hers, there is a disconnect and anger from within.
King Viserys was also not very present in the lives of Alicent's children, both because he was busy with being a King, and because he was deteriorating from sickness. But the biggest failure in his parenting is he never truly loved them the way he loved Rhaenyra because he realizes they came from Otto scheming on his pain, while Rhaenyra came from the love of his life.
The entire reason he named Rhaenyra heir and would never truly consider giving it to Aegon, is because he still felt guilty for killing the love of his life, and wanted to absolve himself of the pain and guilt by being choosing Rhaenyra as his successor. In episode 8 while on milk of the poppy, he even calls Rhaenyra his "only child," this after he mistakenly called Alicent by his first wife's name in the previous episode.
The parental figures for Alicent's children are thus a barely present Viserys who they don't believe actually loves them, Criston Cole, Otto Hightower, and Alicent herself. And what has Alicent been instilling in them since birth? That Rhaenyra will one day kill them. This has led Aegon to drinking himself to sleep as a teenager,and Aemond into hating his b*stard nephews. Her fear and hatred was passed on to them, along with a burden that Aegon doesn't want.
She and Otto both slapped Aegon around for not being dutiful and good, and that is basically the extent of their parenting. And while she can't see herself in Aegon slipping into drinking and whoring and deviancy to cope, we as the viewer should be able to remember how she self harmed as a youngin to cope with the anxiety that came with the duty forced on her by her father.
Alicent being pious publicly really has no bearing on how her kids end up....just like real life.
) - pressuring him about this "inevitable conflict" that's coming with his sister and how the realm is dependent on him, forcing him to marry his other sister, etc all that did was push him towards drinking and whoring. 
