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Short answer. No. Long answer. See below.
People sometime claim that Azure Moon should've had its own "Silver Snow," meaning an option to leave Dimitri as an alternative Blue Lions path like Silver Snow and Crimson Flower do for the Black Eagles.
This showcases a fundamental misunderstanding of just about every single Blue Lion character and most of the Black Eagles too for a few reasons.
Self-Defense vs Invasion
Pretty straight forward. In Crimson Flower, you're choosing to inflict violence on people in the name of Edelgard's vision. In Azure Moon, you're "choosing" to defend yourself from that violence. For the Black Eagles, that's a much more active choice. You are choosing to force bloodshed on people who have never harmed you and likely never would. It's a much more weighty decision. They have to believe in Edelgard enough to kill innocent people for her. All the Blue Lions are choosing is to struggle to defend their homeland from an invasion. This makes the "branching off" from Edelgard much more necessary and have a much bigger impact than "branching off" from Dimitri would.
Edelgard as She Is vs Dimitri as He Could Be
When you side with Edelgard, you are siding with her as she is now. When you side with Dimitri, you are siding with who he could be.
Both Edelgard and Dimitri do things that the player may disagree with. The key difference is that Dimitri's actions are seen as something that needs to change. No one is supporting him while he does terrible things.
This is not true with Edelgard. When you side with her, you are agreeing with everything objectionable that she does and becoming an active participant in all her dirty laundry.
The Blue Lions/Azure Moon needs Dimitri to change. The Black Eagles are choosing or not choosing to support Edelgard as she is, but there's no promise of change.
Edelgard is in Her Right Mind vs Dimitri's Breakdown
Strongly related to the point above, but everything Edelgard does, she does fully in her right mind. Dimitri's in the middle of a mental breakdown. When healthy, Dimitri would never do what he's doing. Edelgard is healthy and doing what she's doing. Once again, this circles back to you choosing to support Edelgard's controversial actions, but not Dimitri's, which is why the split is necessary for the Black Eagles and makes no sense for the Blue Lions.
Childhood Friends vs Classmates
Sort of self-explanatory. Most of the people who are dealing with Dimitri and his bad behavior are people who have known him for years and have formed deep bonds with him. They know him at his best too.
Edelgard is not nearly as close to her classmates, and all the time they spent together - she spent it lying to them and putting them in danger.
It makes far more sense for friends (some more like family) to try and bring a loved one back from the brink every single time than support your class president (and country's heir) who spent the whole semester lying to you and just ordered her goons to murder you every single time. It makes way more sense for the Black Eagles to potentially leave Edelgard than the Blue Lions leave Dimitri.