Yeah. China has one comparable line (Xinjiang-Anhui / Zhundong–Wannan) which is 3300km running at 1100kV. I can't find any concrete numbers on line loss there,

Yeah. China has one comparable line (Xinjiang-Anhui / Zhundong–Wannan) which is 3300km running at 1100kV. I can't find any concrete numbers on line loss there, but I would expect if the voltage is 40-50% higher, keeping all else equal, you'd see a 2x reduction in line loss, so close to 5%. (Of course, this doesn't account for last-mile delivery, or AC/DC conversion losses. But the limiting factor isn't the technology, at this point.)