At least in the United States, defendants did not have a right to lawyer until 1963.
I'm not sure about the Korean legal traditions, but going off my own knowledge of Chinese jurisprudence, I would say a Korean author would likely see a medieval court of law as nothing more than a sham trial where 90% of the conviction is based on hearsay and faulty evidence.
Although its late asf I love learning more so ty, & be warned the following has no backing except Simple Thoughts of the Sleepless;
The dating sim setting seems to me to be more the style of Fantastical Vaguely-European Kingdom you usually see, & based off bias alone I feel like the real "devs" of such a dating wouldn't add that much accuracy.
Also, if I were the devs I'd definitely make it a playable mini game since, if I remember correctly, there was an arrest/court scene in the original & probably include references to ace attorney
Listen ik it's a romance, & ofc I'm invested in alla that as much as I can be (aroace & v low tolerance for romance in general idk how I'm here) BUT WHY DOESNT HE HAVE A LAWYER
Like I'm begging the author go play Ace Attorney & play the soundtrack as u make courtroom scenes I have no data but i believe this would enhance the experience over this arc