Hi Everyone 
For this challenge, I filtered between the dates 01/01/2021 and 31/12/2022 because I don’t know when the football season begins and ends! Additionally, I filtered in rows only related to FIFA tournaments.
I then joined the confederations to the home and away teams and used the -Pivoting- node to calculate the matrix.
Thanks @sryu for the reminder to duplicate the rows where the home and away teams are different in order to make sure all matches are counted in the matrix!
I also wasn’t sure what to do with the shootouts table as the rows seemed to be present in the results table, but perhaps that’s due to a lack of football knowledge! haha
Here is link to my workflow on the hub:
Best wishes
Heather