plotting – How to refine the output of DiscretizeRegion & ImplicitRegion?

This code

DiscretizeRegion(
ImplicitRegion(y/(0.2*Max(x,z)) >= Max(x,z)/Abs(x-z) && y/(0.9*Max(x,z)) <= Max(x,z)/Abs(x-z) && 
x + y + z == 1, {{x, 0, 1}, {y, 0, 1}, {z, 0, 1}}), 
 MaxCellMeasure -> {"Length" -> 0.01}, Method -> "ContourPlot3D", PlotTheme -> "DarkMesh")

produces the graph below, whose lower tails are chopped.

Could it be refined somehow so that the full graph is shown?

enter image description here