Both feature a dislike - to lovers trope, different positions of power, and kind of a cute love story that also gave us real-life couples.
Both featuring badass and acomplished 80s actresses - Jeon In Hwa and Kim Hye Soo respectively - as badass queens controlling the court at the tip of their fingers while protecting their bloodline's life and throne rights. LOTP is more authentic in terms of speech and happenings, as it follows the life of a real person that lived, and is 150 episodes long, while UTQU is on a more dramaticised and fictional storyline.
Both show the story of Jung Nan Jung and Queen Moon Jeong, and showcase the reign of Jungjong and the influence of the royal consorts in the Eulsa Sahwa.
Both feauture the fabulous Jeon In Hwa as the lead , and showcase authentic Joseon speech as well as court/Royal Consort politics.
Soonpoong is a sitcom while WIL is a drama - but both are hilarious af. Featuring fantastic actors (especially in the grandpa/grandma roles) and always funny romance and family moments in a traditional family setting. Both are from the 90s and give that nostalgic feel, plus, feature some legendary actors and actresses in their best days of the youth (like Ha Hee Ra - Choi Min Soo and Song Hye Kyo - Kim So Yeon - Kwon Oh Joong)
Not only do both feature inner court politics and power struggles, but also authentic Joseon speech plus fantastic acting from the respective leads. TOTD is more male-centric and LOTP is more female centric, but both manage to showcase royal politics authentically and true to the times.
(Also both dramas share one "house" - Jeon In Hwa, who plays Queen Munjeong in LOTP (and is on the left side of the poster) is IRL married to Yoo Dong Geun, who plays King Taejong in TOTD. They're nicknamed "sageuk king and queen" because of their frequent, authentic and critically acclaimed portrayals of Joseon figures)
(Also both dramas share one "house" - Jeon In Hwa, who plays Queen Munjeong in LOTP (and is on the left side of the poster) is IRL married to Yoo Dong Geun, who plays King Taejong in TOTD. They're nicknamed "sageuk king and queen" because of their frequent, authentic and critically acclaimed portrayals of Joseon figures)