It's likely that the transmission lines are less of a bottle neck than the frequency conversion. Power lines are pretty darned efficient, and given the cold weather, theyd be more efficient than usual too
https://3dfs.com/articles/wasted-electricity-vs-lost-electri...
Almost 62% of electricity is lost in the grid. AC is the primary reason (matching, vibration, I2R, etc.).
HVDC is WAY better at transmitting power over any appreciable distance.
https://spectrum.ieee.org/energy/the-smarter-grid/chinas-amb...
If America built a network of 20GW HVDC interconnects it would be far more significant infrastructure than building some highways.
I recall that losses after generation due to transmission across the electricity grid are typically about 10%.