Akatsuki no Yona, Arslan Senki Recommendations
Both MC's start off as gullible royality, then grow up.
There is a dispute of who truely should be king.
MC and his/her spear-wielding fighting genius escape.
Maybe some romance in both? one more than the other.
Wars are fought, people are betrayed, strong characers fight each other, great MC's. Who has the claim to the Kingdom?
Both series are set in a historical world, although the settings are different. Both protagonists are a royal prince(ss) and try to deal with the betrayals and politics in their world. They have also a kinda similar personality, imo. They are kind-hearted, grow a lot and nonetheless they are also able to fight.