This tutorial may help you solve this problem (https://www.rilhia.com/tutorials/dynamic-column-order). What you will need to do is set up your file component to read in up to the max number of columns you think may arrive, then use logic similar to that of the tutorial to filter it down to just your required data.
Do you have a complete list of the possible field names? If so, you can build them into your dynamic column filtering logic. Alternatively you could import a column by column list into your tMap as a lookup. For example, you might have the following data for firstname and surname....
Firstname FN
FirstN
FName
Surname SName LastName
LName
If you prepared that data into a table/file with a Firstname and Surname column, like below.....
Firstname, Surname FName, SName
FN, LastName
FirstN, LName
..... you can test your column names against each of the values in this file/table.
This will be a bit tricky to get right, but once the logic is correct you will be able to dynamically add to this list as and when your column headings change.
