Hello @Vs2021 and welcome to Microsoft Q&A. I am not an XML expert but I have a solution.
From my understanding, if such limitation is possible it would be in the fetchxml specifications and not specific to Data Factory.
However I think a much easier solution would be to re-order the columns during the mapping portion of the Copy Activity.
If your sink dataset does not have any schema defined, then you can specify the column order during the mapping portion. See below GIF where I just finish importing schemas where the source schema is defined in dataset, but sink dataset has no schema defined. I drag the order of the mapping.