There aren’t strict requirements on the difficulty of minigames; the rule is a gentle reminder to consider the players’ experience and prioritize accessibility.
A popular example is when Cuphead locks you out of the final two bosses and the game’s ending if you only fought in simple (easy) mode. There was significant backlash, as players weren’t informed of this effect from the start, and those who weren’t fully able-bodied may not ever experience the entire story.
Visual novels are narratively focused first and foremost. Is the mechanic so integral to the plot that content may be locked away from certain players? Dynamic difficulty adjustments can be made, but it may be out of the scope of this jam.
Ultimately, it’s up to you, and your entry would not be disqualified from the jam regardless of how you choose to implement the minigames.