Hi @Kryu
Another way would be use to connect excel as database and use sql queries to perform
But this would only possible if you add the second excel sheet data into the first excel as another sheet
So first excel file would have 2 sheets : Sheet1 and Sheet2
Now connect to excel using sql connection and use inner join to join two tables based on a column or combination of 2 or more column conditions. Take this as an example
I have an excel file having two sheets


See below flow on how to do inner join

SQL query used : SELECT table1.A,table1.B,table1.C FROM [Sheet1$] as table1 INNER JOIN [Sheet2$] as table2 on table1.A=table2.A
Output of this sql query would be :

[But you want to make the power automate flow in such a way that before performing this sql operation, add the second excel file data to first excel file as another sheet and once sql query is performed, delete that newly added sheet if needed ]
I know it would be little complex at design part, But you can give a try and see if it gives you expected results or not 🙂
Hope it helps
@Agnius @lbendlin let me know your thoughts on this as well 🙂