Calculation takes long time

Hello to everyone.
First question: The values in column E: E based on the values of column D: D. How can that value in E:E with ”Data Validation” to be no less than the previous value? (for example: Golf 1 to have a value greater than the previous value, Golf 2 to have a value greater than the previous value…)
The second question: In column I2:I20 I set the formula “{=IF(ISERROR(IF(OR(D2="",H2=""),"",LARGE(IF($D$1:$D2=D2,$H$1:$H2),1))-IF(IF(ISERROR(LARGE(IF($D$1:$D2=D2,$H$1:$H2),2)),"",LARGE(IF($D$1:$D2=D2,$H$1:$H2),2))=0,"",IF(ISERROR(LARGE(IF($D$1:$D2=D2,$H$1:$H2),2)),"",LARGE(IF($D$1:$D2=D2,$H$1:$H2),2)))),"",IF(OR(D2="",H2=""),"",LARGE(IF($D$1:$D2=D2,$H$1:$H2),1))-IF(IF(ISERROR(LARGE(IF($D$1:$D2=D2,$H$1:$H2),2)),"",LARGE(IF($D$1:$D2=D2,$H$1:$H2),2))=0,"",IF(ISERROR(LARGE(IF($D$1:$D2=D2,$H$1:$H2),2)),"",LARGE(IF($D$1:$D2=D2,$H$1:$H2),2))))} and works wonders. But if the copy that formula to the end I2:I1048576 then opening Excel and calculation takes 20 to 30 min.

How can I eliminate this?