Exporting boards with sub-items

Hi, i have a question about the structure of the xls I get when I export a board with sub-items.

My board has items (which are individual clients) and sub-items (which are all the jobs to be done for each client). I need a list of just the sub-items that I can work with (e.g. sort by type and date rather than by client)

If I export the whole board with sub items the structure is a mess because the column structures of items and sub items are different, so I have to spend time deleting parent items before I can work with it.

Ways I could think of working around this are:
If I could export only the sub-items to excel without the parent items, which would give me a clean xls structure, but I can’t see a way to do this
If I could automate the creation of a linked item in a separate board each time a sub-item is created in this board, so I have a board with just the sub-items and again I could export that one to excel. Again i’m not sure whether this is possible

In either case, and even if I am just going to have to clean up the weirdly structured xls export I get now, it would be really helpful to have an option to automatically mirror the item name in every sub-item created under it. At the moment I’m doing that by manually adding tags when the sub-item is created but that’s clunky.

Grateful for any advice

Joanna