Power query too slow

[A_Limiti]

Hi all,

New here and hope to find someone ready to help me. My Excel Power Query app is loading data from a folder. The datas have, for some column, different headings so i found a workaround on youtube: I created a list of the headers, made it unique, converted to a table and then filtered and loaded back again to expand the new table. I hope I've been clear enough. 

From this moment on power query turns really slow in loading the data and I'm pretty sure the issued step are the ones I have of the Heading list and the Filtered Heading list. I attach below some image representing the steps used. 

Really hope someone can help in improving the script and make it faster, maybe even using another workaround to reach the point I need.

Heading List:

Heading list

Heading list converted to table:

Filtered table from unwanted values:

Heading list filtered:

Final result with expanded table of filtered headings:

[dufoq3]

Can you share maybe 2 files with dummy data and provide expected result based on sample files?

[A_Limiti]

Thanks for reply. I actually can't, the files are restricted. If you need some more information by screenshots or direct formulas I can provide.

many thanks

[dufoq3]

Just provide dummy data and expected result like I mentioned before. Without that I can't help you.

[A_Limiti]

I'm sorry about that but as said, I'm not able in any way to directly upload the files. Is there any suggestion you can give me to better understand why the list of headers slow down so drastically the power query steps?

[dufoq3]

I haven't ask you to upload your files. I asked for dummy data. So you should preserve important columns, but put there only few dummy rows like Name: John Doe, Value: 123 etc...