They are not going to recast Luke after Mando for deaging for an entire series. Too expensive. Plus as a good as the Zahn books are they are not canon. I am curious to see how much they incorporate from his stories or if they merge his story into canon.The Thrawn trilogy happened 5 years after RotJ, and Ahsoka is older than Luke. Even if you take the time frame this is supposedly happening in DSW Luke is still in his prime.
Oh, and there is such a thing as recasting.
This isn’t about white frightists (whatever that is), this is about Hollywood being totally bereft of talent and creativity.
Keep in mind they approached Zahn about what they are doing and he could have said no. They also made him part of the process and invited him to help. The fact they did this at all seems to refute your narrative as they are inviting one of the most talented authors in the verse to participate. That’s more than a courtesy.