Both FLs are quirky, cute, and a bit forward/flirty toward the ML, chasing him first. Both couples work together to investigate cases and solve mysteries. The pacing, tone, setting, and feel is very similar, as well.
Both dramas have a similar feel, are light in tone with some darker elements, and focus primarily on mystery/investigation with a slow burn romance between the main couple who solve cases together. The ML actor of HDRA is a supporting character (half of the secondary couple) in MM.
Both are historical dramas in which the FL has a genetic illness that will cause her to die young so she spends her days searching for a man (either to fall in love before she dies or to cure her). Both dramas have a mystery/investigation aspect (HDRA more so) and a mix of humor and sadness.
Both dramas are historical/mystery genres in which the couple works together to solve crimes. The MLs are cold and initially uninterested in the more flirtatious FLs.
I have nothing to say much as usual but, I watched both dramas and the female lead is very funny and good at attracting people's attention if you like to get Her then this dramas that i recommend you'll like too.