Sadly not. If they are the same merchant, say Amazon and you’ve put them in Shopping, then you can change one and it will prompt you to change them all forwards/backwards. But that would be on a per merchant basis. If you’ve shopped at 100 places then you’ll need to do it 100 times.
But you can’t select a category and move all in that category to another.
You can search for the category though (on iOS) so you can easily see what’s left that you haven’t moved.