shaders – Quixel asset to unity

I downloaded asset from Quixel, I’m using Unity HDRP, the problem I am facing is how to properly create a mask map cause the asset from Quixel doesn’t have metalness map where in HDRP mask map it requires channel R should be metalness map, and the base map requires RGB color and I’ve got diffuse map from the asset, to put diffuse map to the basemap slot the right way to do? I’m fairly new to the channel, so put it simple

1.How to pack channels for mask map if no metalness map in the asset, what to do with the empty channel

2.Is it right to put diffuse map to basemap slot?

3.What to do with the detail map in the maskmap , the same as to no metalness map provided in the asset.

4.Another question is heightmap, Unity provide pixsel mode and vertex mode, what is the consideration before choose the displacement mode, When I choose pixsel mode, the whole texture seems to be lowered down not the pixsel on the texture surface bumped or lowered down, it is the whole texture moved.

Thanks for answering these!