Changed to
//Lng/Lat Points converted to UE XY
let Xnew = ((((MapSizeUE - 1) * Scale) / MapRangeX) * Long) - Xm
let Ynew = (((((MapSizeUE - 1) * Scale) / MapRangeY) * Lat) - Ym) * -1
Xnew and Ynew
UEx: -48232072.331334196 UEy: -70635940.09160204
Still off.
Thank you for helping with this.