Somehow, I was not able to find easily the command to remove all jobs in a single namespace. It could be that I just missed it, but I hope after this, no one needs to spend too much time to find it.
kubectl delete jobs --all -n <namespace>
And on top of it, you can also use the field selector to delete jobs based on their labels.
kubectl delete jobs --field-selector status.successful=0 -n <namespace>