Google Sheets Formula Help needed - Vlookup/Index/Match

this is my first time on here, I'm hoping someone can help me :)

I have a formula that finds the final occurrence of a value in a range and gives me the date for that occurrence

=ArrayFormula(LOOKUP(2,1/('Active Inventory'!$F$2:$F$400=$G3),'Active Inventory'!$A$2:$A$400))

It works great, the problem is I need to return the next date in the cells below the given one. here is a formula that gives me the next cell (date) after of the first occurrence of my value

=INDEX('Active Inventory'!$A$2:$A$400,MATCH($G8,'Active Inventory'!$F$2:$F$400,0)+1,)

but how do I get the next Date down (even when there are some cells below with the same date) after the last occurrence of my value?