The 1180 will at most be 10-15% better than a 1080ti.
Heck the titan V barely scratches out a 25% lead for 3.5x the price.
For the proper usage of something like the 8kx, we will need something at least twice as good as what we got. That's at least 5-10 years away. And with how transistor scaling is panning out recently it just might not happen at all.
Simply put. Moore's marketing gimmick has been dead for a decade.
And Pimax was being commically optimistic when it mentioned a 1080ti for 8kx.
You will need the 1080ti just for the regular 8k.
And if you expect to downsample the 8kx is going to look worse than the 8k.
SLI is also not a basket I will put any money in unless you play Raw data exclusively.