Sorry, I am not able to answer the question on the X1DII EVF and focusing speed.
But... why not a Z7 or, according to rumors, soon to be announced Z7s? It’s cheaper (and can be found sevomd hand), will be serviceable in Pukhet, more compact, has an top class EVF, has a UI very similar to the of the D850, has very similar image quality, outstanding lenses, IBIS, an AF that’s much better for sure, can use your existing set of Nikon lenses,...
Cheers,
Bernard