So...
Next month Gintama will not end, this is 100% fact.
Many plots was't explained.
The future Shinpachi v2 will travel alone to the past (Joui War).
Just look on chapter 454, (page 13-15) this is Shinpachi.
https://mangadex.org/chapter/70213/13
Future Shinpachi v2 hidded his identity with this "gag name". Many times in show, Shinpachi said something like that he is a shadow and Gintoki is a light (even in ending of ep. 3/ chapter 1).
Unknow person was shown even in 2nd movie, that person was 5th Joui member (Future Shinpachi v2).
That moment was on final fight, when Blight/ Enmi was send violet, evil energy/ virus. Then we saw at 1st Joui Sakamoto, 2nd Joui Katsura, 3rd Joui Takasugi and then Future Katsura said: "This is..., No, this is impossibile...", 4th Unknow Person (Future Shinpachi v2), 5th Joui Gintoki and Gintoki.
That 4 th person wasn't Joui Gintoki because we seen in next scene, that Joui Gintoki have white uniform and we only can see that he is wearing black "shield?" only on his stomach and unknown person had "green?" and black "shield?" not only on his stomach and even on his back. 2nd fact: Joui Gintoki haven't godspeed, so he wasn't been able to jump alone that fast, to the destroyed ship and then go help Gintoki and Future Kagura and Future Shinpachi v1.
Just trust me and my Intuition.
Next month they just will annouce: "We are going move to Shounen Jump again" and there will be little pause (maybe 3 months?).