As you mentioned you need to unzip the files in the subfolders also, below is a suggestion for this process.
you can write a powershell script or command line script to get the full path of the zip files and write to a text file. Call d powershell using Uipath activity.
then loop through each line in the text file and unzip it.
If you can use powershell plz let me know. I can share the script