I have this formula in Google sheets that helps me get the order of occurrence of an email when the email is a duplicate : =IF(COUNTIF($B$3:B3,B3)=1,1,COUNTIF($B$3:B3,B3))

I’m trying to get the same formula but in an ARRAYFORMULA. Usually I would use MAP/LAMBDA to solve the issue, but in this case the arrays are of different size so it does not work.

Here is my spreadsheet to help better understand : https://docs.google.com/spreadsheets/d/1J0xHUn-qZh2pNPxAB24bQL79XrPgLFBxpnL43MCnoy4/edit?gid=0#gid=0

Appreciate any kind of help on this.
Thank you