high voltage DC, it was a bad idea in the past due to the difficulty of changing voltage, but Buck boost converters exist now, as due inverters.
Nah. We’ll go more primitive. We’ll do all our voltage and AC/DC conversions…mechanically! Do what they did to power DC subway systems back at the start of the 20th century. Just have a big AC motor directly coupled to a big DC generator! And we can use gearing to convert voltages! Let’s bring a needlessly complex and steampunk aesthetic to our electric grid!