It's only a problem if you try to fit it into the TOS universe, which the showrunners very clearly and deliberately aren't. It's like trying to fit Ben Affleck's Batmobile into a chronology of the Adam West Batman universe.
Supposedly it's this TNG-era design that Eaves' made for a fan club that was the basis for the Shenzhou.
In other words you're agreeing that it is and it looks like a TNG ship which is exactly what I said in the first place. It's the Akiraprise all over again.