Is there any way to remove an instance from the list once it has been terminated? Not filter out, but actually remove?
No, you need to wait until the instance disappear.
After you terminate an instance, it remains visible in the console for a short while, and then the entry is automatically deleted. You cannot delete the terminated instance entry yourself. After an instance is terminated, resources such as tags and volumes are gradually disassociated from the instance and may no longer be visible on the terminated instance after a short while.