The Knight actually isn't trying to make the Roaring happen
They probably don't want the roaring to happen, otherwise they'd just start it by spamming black fountains. Either that or they need specific circumstances for the roaring for their true goals to come to fruition; Maybe the roaring does happen but it doesn't matter cuz hometown is a simulation or something and they're trying to break out of it. I think the most likely thing is that the knight gang wants to bring back Dess in some capacity (and perhaps something else) and they need to go about it in a specific way.
So far it seems like
>The knight wants us (Susie, Ralsei, Player) to view them as an oppositional force
>They don't actually want to stop us though.
>The knight is seemingly smart enough to plan and hold back to adhere to their plans.
Side tangent, but the way I interpreted the whole knight fight stuff is that the knight is trying to 1. Stall, 2. Make us think that we're after Toriel (Knight could have done this either because using Toriel as a prop was the best way to stall until Undyne gets here, or because they wanted to show us that the Knight is trying to kidnap specific people, instead of just like stealing Undyne for attacking her). The way I interpreted "beating" the knight is that before this the knight was holding back to stall for time until Undyne arrives, but after the piece of the sword breaks off the knight realises "they can actually hurt me (a little bit)" so they stop playing and swoon everyone. This is consistent with the fact they can pretty easily maul everyone in chapter 4, and also literally one shot Flowery who is about as strong as the "fun" Gang. Additionally, the reason that Kris does more damage when Susie/Ralsei is downed isn't because he's throwing a hissy fit, but because he's trying to stall as well, and not tip the others off to the fact he's not pulling his weight. Anyway,
>The knight waits a really long time to do anything, mainly in chapter 3 and 5. For chapter 3 we know because he wanted to bait undyne to kidnap her, but for chapter 5 we don't know. Chapter 3 and 5 both ended at night, so maybe it needs to be night for the knight to be active in hometown? Maybe they wanted to minimise who could see them in hometown? Or maybe they're a holiday and they were occupied before this.
>The knight either seemingly needs the bunker codes for something, wants to stop us getting in from the bunker, wants to give us a reason to try and get into the bunker, or wants to delay us getting into the bunker. Idk
Yeah a lot of mysteries
Modders don't make the game and the vanilla game says otherwise.
Thats because the game is retarded. Kris is obviously a man, and this isn't exactly equivalent to people saying shit like "OMG THIS CHARACTER IS GAY OR TRANS OR BLAH BLAH BLAH" for whatever reason, because the difference is that everyone is a man or a woman and "Non-binary" doesn't exist, so our observations are actually based on reality instead of delusions. Also, Toby hasn't even clarified if Kris is meant to be "Non-binary" or "up-to-interpretation" which is really silly, just clarify it ffs.