By "ectopic thyroid tissue" I assume you mean either a lymph node or some tissue that seemed detached from the normal thyroid.
If there is Papillary thyroid cancer anywhere in the neck, outside the thyroid, the minimal surgery is total thyroid removal and central compartment dissection. The next issue is a careful ultrasound evaulation of the rest of the neck to determine if lateral neck dissection is needed.
The rock-hard L lobe is very concerning as the possible "primary" tumor.
Thank you for your response. This information was very helpful.