I will be shooting landscapes. But with ISO 400 a tripod is not needed as much.
Ektar 100 pushed 2 stops will be the best pushed saturated film you can get. It won't fall apart like E-6 does.
Otherwise, you have 400X for E-6 for 400 speed and that's it.
If you don't mind C-41 and don't need a slide that you intend on projecting in person, then Portra 800 has high saturation and low contrast to capture high contrast landscapes without losing anything. Though Portra 400 is much better for 35mm, saturation a bit lower, and contrast higher, but has no problem with high contrast scenes.