Source: https://www.wowhead.com/quest=4362/the-fate-of-the-kingdom#:~:text=This%20quest%20was%20marked%20obsolete,clutches%20of%20Emperor%20Dagran%20Thaurissan.

And also, I cannot get the quest in-game (WOTLK).

Just to clarify - the source you linked is for Retail, where that quest is indeed no longer available, but it is certainly available in Wrath and was even available after Cata.

Can you do me a favor and type the following lines into your chatbox ingame, and share the results?

/dump C_QuestLog.IsQuestFlaggedCompleted(3702)
/dump C_QuestLog.IsQuestFlaggedCompleted(4341)
/dump C_QuestLog.IsQuestFlaggedCompleted(4342)
/dump C_QuestLog.IsQuestFlaggedCompleted(4361)
/dump C_QuestLog.IsQuestFlaggedCompleted(4362)

Hey @mazerakham could you run the commands above?

I believe i fixed this chain quest a long time ago