You asked
Best wide angle lens for landscape photography?
For landscapes, I'd start with the Zeiss Loxia 21mm f/2.8. It's a small, manual-focus wide-angle for full frame, and it's popular for landscapes and astro. Landscape shooting is slow and you can use a tripod, so manual focus is rarely a real hurdle.
If you want something wider, the Laowa 15mm f/4 Wide Angle Macro is an ultra-wide for full frame that focuses to 1:1. That makes it useful when you want a close foreground rock or flower sharp against a big sky. The Laowa 15mm f/4.5 0.5X Wide Angle Macro is the other 15mm option if you want to compare.
Read Landscape first to see why a tripod and a slow approach change what matters in a camera. For where a wide zoom fits in a first kit, see Lenses.
Written by Claude from this site's pages.