In theory you can do HVDC over long distances. In practice that doesn't help much. Power would normally want to run north to south (not gonna do HVDC across the oceans anytime soon), and so the terminator hits you at the same time everywhere. It's got to be batteries if you want PV at scale.

The practical difficulties aren't really long distance transmission though. They're political and engineering. Spain had a massive blackout recently because a PV farm in the south west developed a timing glitch and they couldn't control the grid frequency - that nearly took out all of Europe and the power wasn't even being transmitted long distance! The level of trust you need to build a giant integrated continent-wide power grid is off the charts and it's not clear it's sustainable over the long run. E.g. the EU threatened to cut Britain's electricity supplies during Brexit as a negotiating tactic and that wasn't even war.