I like the reminder at the beginning. Some readers often forgot that not all authors take a short route in explaining and showing the main foundation of a story. When I started this manhwa and noticed that it revolves around political conflicts I knew that it will take so long especially if Ian is a reincarnation of Brian. This current season is basically about how those two met and fell for Brian but it also shows how the two countries are built to what they are in the present. This is a political romance fantasy manhwa. The flashback is going to be long if the author decided to be very detailed.
Remember this; a lot of authors spends days, months even years planning and constructing their plots and characters. They made the story for their satisfaction first before the audience. They want to share their work and ideas that took a long time to construct. This manhwa is a prime example of careful planning of world and character building. Stop complaining about not seeing Ian and how long the backstory is taking. Its already set and planned. The author won't change their story telling style to accomodate readers who have no patience and wants a fast paced story.