Automatic date formula

I have purchase data:
2 Eiger Starter Daypack 16L Blue, purchased on 2 July 2023
2 Eiger Starter Daypack 16L Olive, purchased on 2 July 2023
2 Eiger Starter Daypack 16L Blue, purchased on 3 July 2023

I want automatic formula in my sales data :
If, 1 Eiger Starter Daypack 16L Blue sold on 5 July 2023, the purchase date will be shown 2 July 2023
1 Eiger Starter Daypack 16L Blue sold on 6 July 2023, the purchase date will be shown 2 July 2023

but
If, 2 Eiger Starter Daypack 16L Blue sold from 1 buyer on 5 July 2023, the purchase date will be shown 2 July 2023
1 Eiger Starter Daypack 16L Blue sold from 1 buyer on 5 July 2023, the purchase date will be shown 3 July 2023

Kindly help.
Thank you.

Dear John,

I mean, if the item 1 Tripwalk navy is sold on 5 July, so the purchase date will be shown 2 July, and then if 1 Tripwalk navy is sold on 5 July, so the purchase date will be shown 2 July too because I purchased 2 Tripwalk Navy on 2 July.

I have 2 sheets data : purchase data and sales data

Thank you.

Dear Jate,

Here I attach the data.

Thank you.

I want a formula on sheet : Sales data, column : "Purchase Date" that is referenced from Purchase Data sheet.
So I don't fill it manually.
Thank you.

Thank you so much Jete!
Really appreciate it..

Dear Jete,

If you don't mind could explain me about the formula :
=INDEX(Purchase!A$4:A$58,AGGREGATE(15,6,(ROW(Purchase!A$4:A$58)-ROW(Purchase!A$3))/(Purchase!D$4:D$58=D4)/(Purchase!E$4:E$58=E4)/(Purchase!N$4:N$57>=P4),1))

Because I really don't get it.
Thank you.

Dear Jete,

I still don't understand.
Kindly explain.
Thank you.

Herewith I attach the file again.
On purchase date column last row the balance should be 2 not -2.
Hope you understand what I mean.
Thank you.

No Jete on 1st nov 3 were purchased from Shopee, 1 from lazada, and then 1 from shopee again (diferent price).
So I bought 5 bags on that date.
On sales data sheet, 4 were sold on 3rd Nov (just simulation)
On balance column the last row should show 1, not -2 (it calculate from the same date, 1st november 1-3 = -2)
My current formula can't cover all the parameter so the result is -2, because I don't use cummulative.
Hope you understand.
Thank you.

Dear Jete,

I think the formula is not correct because the balance :
1-Nov-23 Shopee 3 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 5
1-Nov-23 Shopee 1 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 5
1-Nov-23 Shopee 1 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 5

The balance shows 5 bags if there's no selling.
It sums 3+1+1.

The result shoud be :
1-Nov-23 Shopee 3 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 3
1-Nov-23 Shopee 1 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 1
1-Nov-23 Shopee 1 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 1

Thank you.

Dear Jete,

If I copy the formula the result still not the result I want
The balance result :
1-Nov-23 Shopee 3 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 3
1-Nov-23 Shopee 1 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 4
1-Nov-23 Shopee 1 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 5

I want the balance if none are sold :
1-Nov-23 Shopee 3 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 3
1-Nov-23 Shopee 1 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 1
1-Nov-23 Shopee 1 Eiger X-Cruisage Canvas 20L Laptop Backpack Beige 1

Because in Balance Total I want the value of Balance * Unit Price, since the price is not the same from every purchase.
Hope you understand.
Thank you.

Thanks Jete.. solved!

But I modified a little bit to :

=IF(E4="-";"-";IF(SUMIFS(C$4:C4;A$4:A4;A4;B$4:B4;B4;D$4:D4;D4;E$4:E4;E4;G$4:G4;G4)-COUNTIFS(Sales!G$4:G$79;B4;Sales!$D$4:$D$79;Purchase!D4;Sales!$E$4:$E$79;Purchase!E4;Sales!$F$4:$F$79;Purchase!A4;Sales!H$4:H$79;Purchase!G4)=0;"sold";SUMIFS(C$4:C4;A$4:A4;A4;B$4:B4;B4;D$4:D4;D4;E$4:E4;E4;G$4:G4;G4)-COUNTIFS(Sales!G$4:G$79;B4;Sales!$D$4:$D$79;Purchase!D4;Sales!$E$4:$E$79;Purchase!E4;Sales!$F$4:$F$79;Purchase!A4;Sales!H$4:H$79;Purchase!G4)))

because I want if the result is "0" = "sold"

Thanks.