Deleting iCloud files from iPad, not MacBook

Not possible. iCloud is a synchronization service. Anything you remove from a device signed into iCloud is also removed from iCloud and by extension from any other devices connected to the account.

You can turn off iCloud on the iPad and delete anything locally then and it won't be deleted from anywhere else though.

If you are talking about files in iCloud Drive, then they may not even be on your iPad at all, so deleting them will have no effect on your storage. Here is part of what I see in Files>iCloud Drive:

The icon with the down arrow means that this file is not stored on my iPad, but it's available form iCloud if I click on it. Like this one, almost all the files are not stored on my iPad.

If I wish, I can can keep a file on my iPad by long pressing on the file name

and choosing "Keep Downloaded."

You may want to see this:

Understanding iCloud Drive - Apple Community