I said this before but I have ideas on how the eating system could be revamped. Instead of eating 50 pieces of black garlic to replenish Ryo's health, Ryo should only need to eat 3 times a day (maximum). The eating system could tie in with the rapport system, both with Shenhua (and even Ren), along with locals in bars and restaurants.
Shenhua cooks breakfast in the morning and choosing to eat with her increases your bond. While eating, you discuss a bunch of different topics. Basically, you get the reward of more dialogue with her. The deeper the bond, the more personal the conversations become.
Similarly, locals of an area could be quite cold to Ryo at first, but spending time in bars and restaurants may increase the bond Ryo has with a particular patron or owner. Rather than have a difficulty level, make the game more or less difficult depending on how much effort you put into your investigations.
I don't think Ryo's stamina should deplete throughout the day like in Shenmue 3, but rather, the overall HP for Ryo should increase/decrease after a night's sleep, based on how much he is eating. This is essentially encourages the player to talk to Shenhua, visit bars, restaurants, etc, but also rewards them, since Ryo building a rapport with people will lead to new pieces of dialogue and even sidequests/opportunities.