Both Nikon D3400 and Fujifilm X-E3 have APS-C sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another similarity between these two cameras is that both Fujifilm X-E3 and Nikon D3400 sensors lack anti-alias (Low-Pass) filters. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the D3400 and X-E3 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D3400 and Fujifilm X-E3 Cameras
Nikon D3400 and Fujifilm X-E3 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Nikon D3400
or the
Fujifilm X-E3 ,
including hyperfocal distance.
