How to stop transfer of files to iCloud
If you just can't wait for it to finish (I would just ignore and wait), you could disconnect from the network and then restart.

The iCloud sync respects the local filesystem, so any change there should be immediate once the network / restart changes.

You can log into iCloud.com as well once you clean things up / re-enable the network and give iCloud upload process a few tens of minutes to react and clean up.

I've had 10 GB go up one day, so as long as you aren't paying for the bandwidth and are close to an Apple data center (same half of a continent), 4 GB shouldn't take that long either to get uploaded and then delete.