Princess, She Really Doesn't Want to Ascend the Throne

The taciturn and loyal dog male protagonist × the powerful female protagonist "I am the eldest princess, because only the title of the eldest princess can be worthy of my title." "When I met Your Highness, she was as dazzling as the sun in the sky. I want her to continue to shine. If anyone tries to cover up her light, I will try my best to kill him." (The plot is purely fictitious, please forgive me if there are any illogicalities)