Echo of a Letter

Both have Chinese influences and Male Lead chasing mc. Even though mc fell in love unknowingly. Both have a period of unrequited love leading to a sweet romance. Some action and loses of loved ones are also similar. Overall the vibes resembles each other and cinematography is better in this one. The only difference would be of AI usage in echo of a letter.

Both the shows have similar tropes (stalking, obsession, business, childhood savior, family troubles, unrequited love, yearning etc,). Hua Yong and Chen Wan were saved/shown kindness by their future partners during their childhood thus becoming the light to their dark world. Both of them had traumatic and dark/abusive childhood (family issues) so when Sheng Shaoyou and Zhao Shengge appeared, both were simply smitten and have been in an unrequited love for many years.

However, Hua Yong and Chen Wan's obsession is quite different from one another. Hua Yong wanted Sheng Shaoyou, he actively pursued him, and wanted a life with him. Hua Yong was also quite possessive. However, Chen Wan is the complete opposite, he does not want to be with Zhao Shengge, he just wants to protect him from afar, he feels he is not worthy of him. For him as long as Zhao Shengge is safe and happy, it is enough for him. Also there is a small misunderstanding (resolved quite quickly) that ZSG is engaged, CW actually risked his life to save the supposed fiancee. His love is PURE DEVOTION. There is also a line "Even if he sees ZSG once out of 10 times, it is enough for him" like DAMN.

Also, it seems like there is a possibility that CW can become HY, there are many instances where CW admitted that if he crossed the line once he would make ZSG his even against ZSG's will so, both of them do seem to have pyscho tendencies, CW has been seeking therapy to suppress his craziness. So, I would say CW is pre-Hua Yong suppressed by therapy and medicine. Also both have a thing for chopping off hands/fingers.