You might reduce the issue a bit if you are using 4K textures but, it will never go away entirely.
The ground scenery is made in tiles, because it was designed for FSX but not using slow FS8 code that everybody in that era were using for FSX so, we had to split the scenery to reduce flickering that would otherwise appear when using native FSX code instead of slow FS8 code.
Today, native P3D4 sceneries ( like KORD V2 ) doesn't need to use those methods, which means in case we'll redo a remake for JFK V2 sometime, it won't have these problems.