Your daughter’s online schooling is an unnatural social setting for a teen. Without interaction with her peers, she is missing out on the discussions that teens share about preparing for their future and transitioning into the next phase of life.
At 18, your daughter would typically have a job, be making plans for college, maybe considering entering the military or receiving training to enter the workforce.
She needs responsibilities and chores around the house. Put her in charge of preparing the family’s evening meal once a week. Make the Internet and other electronic communication off-limits for the entire family at a certain time of the day. Help her become more adapted to normal work and school schedules. Have her explore viable job options. Insist that she get this vital experience while you are still supporting her. She cannot wait until she is out on her own and financially responsible for herself.
Your daughter can decline counseling if she can prove that she does not need it. So, let her know what she is required to do to prove her normalcy and if she does not comply, ensure that she attend counseling sessions. This is not optional.