This is very difficult as there are personal aspects. My travel lenses are the 18-55 and 55-200 because of size, comparative light weight and they give good results. I have a selection of primes, among them the 35 and 50 f2. I tend to use them on a X-E3 as my always with me setup. They give very good results. My best primes, however are the 56mm and 90mm. The 56 gives brilliant results on an X-T3.
I have not tried the f2.8 zooms as I believe them to be bigger and heavier, but most people say they give even better results. The 35 and 50 f2 on the E3 are a very portable, neat package.
You say you want to take landscapes. Will you hike? Are size, weight and balance on your camera body considerations? Are you into wide angle landscapes, or do detail landscapes with longer lenses? Personally I like zooms for landscapes as when I find a viewpoint, it can be hard to shift position to get the coverage I want with a prime.
Only you know the answer to these questions.
Best wishes,
Jonathan