4G+ (m1803d5xe Vs m1803d5xa)

Hello guys, I sold my Mi Mix 2 and bought a Mi Mix 2S (m1803d5xe model).
In the Mi Mix 2 (global version) I could get 4G+ but with my Mi Mix 2 I can't, only 4G.

I have seen some people that can get 4g+ but with m1803d5xa model (globla version).

Is there any major difference or hardware? They look exactly the same, same specs but I can't get 4g+ work in m1803d5xe here in Portugal.
People with m1803d5xa can also in Portugal with the same carrier (Vodafone P).