I have to disagree with you.
It was never actually established that it was a byakugan that Boruto had in the flash forward in chapter 1. That was just fan assumption. You are using visual differences between the anime and manga to doubt that the eye is Jogan, but it should be noted that the eye in the manga didn't show the veins of the byakugan either, so I could use the same visual logic against you. Plus, Ikemoto's art is very different from the anime's. For crying out loud, Konohamaru has an afro in the manga. It isn't really fair to use slight visual differences like the black scalera thing.
Additionally, fan assumption said that his "byakugan" was borrowed from either Hinata or Himawari (who were believed to be dead).
Now would you really rather have Boruto just have some borrowed byakugan eye that he probably can't even use to it's full capacity due to it being borrowed and only one of them, or would you rather he have his own unique dojutsu that is probably way cooler and more powerful than byakugan and that he can use to it's full capacity since it is his own natural eye?