Just registered myself, definitively not a very experienced user myself, but thought of giving you some heads-up. Reinstalling the game (which can easily take hours) is not needed. If you remove the files you added for ReShade or SweetFX (d3d9.dll, dxgi.dll, any .fx files and the reshade of sweetfx dir) your game should be good to go again. If you get a repair button in the launcher, that probably doesn't have anything to do with this. Had that problem way before I started with ReShade on my game. Even before TU came out. Just restart the launcher till it gives you a play button again.
I'm also trying to get ReShade or SweetFX to work on ESO, and no luck on my side ether. I'll let you know tho when and if I get it working.