First off, you got it right, nVidia Experience is crapware and should never be installed on any PC.
Second, your video card can't handle DSR with a 2560x1080 screen (I have the same card, though it's an Asus Strix version), but you can try it then do what will really give you a better experience.
The basic fact is that a single GTX 980 Ti is barely capable of handling 5120x2160 (double your screen res, the only sane form of DSR for Skyrim, which is the 2.00x setting in the nvidia control panel), then you have to consider how much texture VRAM will be required for SSE, which is a lot more than oldrim needs even if you don't use any texture mods. Adding mods only makes it even worse. It will probably work, just barely, but it won't maintain 60fps and will get worse as you add graphically intensive mods.
What I would recommend is that you go with SMAA and disable all other forms of AA. This works fantastically on my huge 4k screen and even with a lot of intense graphics mods I can get around 110-120 fps, though I use frame rate limiting and VSync to keep things sane (especially the shitty physics subsystem Skyrim uses, aptly named Havok if you have ever seen what happens when you load a cluttered save with runaway fps).
So no CSAA, no EQAA, no FSAA, no FXAA, no MLAA, no MSAA, no NSAA, no TAA, no TXAA, no, no SSAA.
SSAA - Basically similar to DSR - renders the scene at high resolution then interpolates back to screen res. Very heavy GPU load resulting in a big fps hit.
MSAA - Basically SSAA but only on polygon edges and it's built into the GPU, really f***s up when transparency is used, so out of the running immediately.
FXAA - Very fast, absolute crap.
TXAA - Eliminates shimmer, works good on fast moving objects, terrible blurring.
MLAA - A bit better than FXAA, same basic concept, only works on ATI/AMD GPUs.
The rest are based on these with a few tricks, some of them specific to certain game engines and either don't apply to Skyrim, or don't produce much different results.
Once you've decided that oversampling is going to strain your GPU too much, the basic question is whether you want post-processing or not. The issue is that if you use inline AA, any lighting effects you use will happen after the AA is done, and will never get fixed unless you add a secondary post-processing AA which not only adds to the load on your GPU but also messes up the first AA pass somewhat.
SMAA is simply the best post-processing you can find, it integrates well with ENB but also works fine without it, and produces the lowest amount of blurring compared to any other post-processing AA. You may get some shimmer in distant water and mountains, but that can be corrected with INI settings and some distant terrain mods. Turn off any and all other forms of AA as they won't give you any better quality without dropping your fps.
My brain is very picky and is bothered by aliasing, especially when I am tired, so when I say that DSR (or any form of oversampling/supersampling) or SMAA are the only good AA, what I mean is that my brain isn't instantly going "OMG THIS LOOKS LIKE CRAP!", and SMAA isn't going to strain your GPU and drop you below 60fps the way DSR will. Try it, turn off all AA and set DSR to 2.00x in the nVidia control panel and see if you don't agree.