Excel Formula in Large File Taking Too Long to Process

I've got a large file with around 290k rows of data in across 12 columns or so. In a new worksheet, I removed the duplicates and have only 2 columns, but still over 100k rows. I used a formula in this new worksheet to return multiple matches across columns. Basically, this formula: {=IFERROR(INDEX(returnvalue,SMALL(IF(lookupvalue=$E5,ROW(returnvalue)-MIN(ROW(returnvalue))+1),COLUMNS($E$5:E5))),"")} which I found from exceljet.

The formula works, but due to the size of the file and amount of cells needed to populate, it's taking forever for the formulas to process and I haven't even tried to do all the cells, just a small portion of them. What would be the best way to get the data I need? Separating the data into multiple files is the only way I can think of at the moment. Is there a faster method?

Perhaps try Power Query?

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