My main complaint is that starting with Al's arc, the whole conflict makes no sense. Also, their parents are incompetent.
First, her father is still young, they have a couple of decades of ruling still in them. So this whole mess is not as urgent as everyone is painting it. There is still time to change things, specially with how her magitech is growing. She saved the country from a dragon, that should shake things up given time.
Second, Al is an idiot. He supposedly loved his sister, but instead of supporting her he decided he would ally with the people who hate her, so that he could then gain the power to manipulate minds, so that he could later betray his supporters and force everyone to accept her? At least that's what I understood to be his plan. It never made much sense to me. His conflict seemed to be that his sister had to step aside because everyone hated her, and he resented her and everyone else for it?
Third, her parents are idiots. Despite being shown as competent, they couldn't even keep an eye on their heir and raise him properly. It's one thing to have a weak position, but at the very least try to prevent uprisings.
Fourth, the whole "inheriting the kingdom" issue revolves around keeping the throne in the family, but she doesn't plan to have children, so her succession is going to run into the same issue.
Fifth, Euphys plan doubles down on the issues that caused this whole mess, which is the nobility's superiority depending on attunement to spirits. So it's a regressive approach.
The smart solution would have been for Al to not be a dumbass and take the throne while supporting Anis. Then none of this would have happened. The second best would be for her parents to start supporting magitech more openly, now that she saved the country from a calamity. Start undermining the religious underpinnings that support the nobility while earning the support of the commoners, as the magitech gives them access to magic. Then, when the time came for her to inherit the throne, the opposition would essentially be defanged. An order of commoner soldiers armed with magitech weapons would form a reliable shield against any nonsense the nobles could try.