Reading off those hard to read graphs, it looks like both solar and imports are up about 3GW in 2025? Why do you say imports increased so much more than solar?
Same with the very bottom set of three plots. Between 2025-2026, there's not much change in solar that I can see, but there's a huge change in night-time and morning imports, which depresses natural gas a ton.
Nighttime generation from SunZia would be a likely cause; at least in California night time wind is stronger than day time, usually, I wonder if New Mexico is the same.
I'd guess if the numbers for grid energy fed to batteries and the output from were compared it might be possible to discern if there was a source of energy that didn't go via the grid and so didn't show up on the stats.