Transmission losses are subject to engineering, and can be as low as you're willing to spend money to get them — as in, if the world all suddenly (magically and unrealistically) decided to be friends, you could put a girdle around the world with only 1 Ω resistance using existing manufacturing capacity[2].
[0] https://www.wolframalpha.com/input?i=Tarifa+Spain+sunrise+21...
[1] https://www.finavia.fi/en/newsroom/2023/what-polar-night-exp...
[2] ~ 12 months global aluminium production, but you could do it