I'm expecting Chapter 5 to, at the bare minimum, get hit with a huge delay for several possible reasons:
>Toby gets hit with false rape/sex pest allegations that force him into hiding and destroy his will to keep working for a few months or a year even after everything gets sorted out
>Toby gets attacked by some crazy Jap for schizo reasons like the Kyoani arsonist and gets hospitalized for a while
>Toby gets ousted by his team Mike Z-style and has his game hijacked and subsequently run into the ground because that's the kind of company that he keeps
>in the worst case scenario, getting arrested or fucking dying because he gets outed as an actual pedo/gets legit murdered by some dude over schizo bullshit, in which case the game never comes out or gets mishandled by his team

While for Undertale, you can cope how they/them is for the sake of self-insert, in Deltarune this "system" falls apart because the whole point is that you are not Kris, but an entity that controls him. Kris is presented as his own person with his own agenda, and this person is clearly a dude.