Abdullah Belaid, I visited your FB timeline & saw beautiful landscapes you’ve photographed. You’ll be happy with a full frame like the 5D IV or equivalent, coupled with good L lenses you can collect over time. (I use LEE filters too for landscapes.)Your 800D, being a good camera, should not be sold & be used to complement the FF when you need an extra 1.6x reach or for general lightweight walkaround streetscapes.