FILTER between columns

I have thousands of data in 2 columns

First one is ordered by export and the other by latest activity. The export columns has more queries than the latest activity. (can't change the export to the latest activity)

I stuck in finding a way to get all the email addresses from the latest activity and check where they are in the export list.And important sidenote: the latest activity list is incomplete at the end of each query. As the example below.

name1@mail.country  name3@mail.cname2@mail.country  name4@mail.counname3@mail.country  name6name4@mail.country  name1@maname6@mail.country  name5@mail.countryname5@mail.country  name2@maname10@mail.country name3000@mail.country

I need to find and keep all the duplicates and remove all the othersSo in this case name10@mail.country & name3000@mail.country should be deleted.

Is this something I can do in Sheets automated instead of manually finding each one by cmd+f.

I have about 5000 active users I need to filter out.fingerscrossed

The expected result would be that I can exclude everything from the first column based on everything from the second column.

Link for example:

https://docs.google.com/spreadsheets/d/1PnnBDR8mKn77Jtf6E9Y4fYGlghxxVL9SguCSH3u-bp8/edit?usp=sharing