Recents folder in Finder

The Recents folder doesn't store an additional copy of anything. For example, if you don't have iCloud Drive turned on, any time you access a file in your Documents folder it will show in the Recents folder -- but there aren't 2 copies of that file. If you delete it from the Recents folder it is deleted from the Documents folder.

With iCloud Drive turned on, if you have accessed an iCloud Drive file it will show in the Recents folder and also in the iCloud Drive folder on your Mac. If you delete it from the Recents folder, that deletes the local copy from the iCloud Drive folder on your Mac -- and that deletion then syncs to iCloud and it is deleted from there.

If you don't delete them now and they are eventually gone from your Recents folder, they will still be in the iCloud Drive folder on your Mac (unless they are automatically Optimized as mentioned in my previous post).

iCloud is not designed as a cloud-only storage service. In most cases what is on iCloud will also have a local copy on your Mac. If you delete the copy on the Mac it will also delete from iCloud.

iCloud Drive syncs deletions -- i.e., if you delete a file that is in iCloud Drive on your device, it deletes from iCloud.

If your objective is to free up space on your Mac, you may want to turn on Apple menu > System Preferences > iCloud > iCloud Drive - Options > Optimize Mac Storage. The following may also help: iCloud Drive FAQ - Apple Support