Print-level sharpness, and animation without flickering, are mutually exclusive. You’ll have to go to extremes in order to get both, and don’t be surprised if you have to sacrifice one for the other.
Gaussian-2 is recommended for animation that’s a 2k render, smaller would be less, larger would be more. I’ve never even heard of a print guy using gaussian, because it softens, where they prefer something that sharpens, like Mitchell.
I have had the same trouble, with a starfield map, what I do is to turn off filtering completely, and raise anti-aliasing / motion blur enough to compensate. Higher res always helps too, as long as the texture itself is higher res ( not just scaled up ).