When an email comes in with a zipped file, you can use the process attachments feature to save that zipped file into a folder. In the same automation, you can use the compression feature to "decompress" the file and save the unzipped file in the folder along with the zipped file. To do this, you need to make sure that in the message source, within properties, you don't have the tick box to automatically unzip attachments.
Here are the screenshots for how to build the automation:-