I had to lay off an employee who was incompetent but nice. She was constantly anxious and paralyzed by blockers. I did everything I could to reduce her stress levels, give her mentors, ensure her work was reasonable and achievable. She could not make forwards progress unless she had a pair programmer basically doing the work for her.

She was in the wrong job at the wrong time. She didn't have the skillset to have a successful start. Her work patterns were unhealthy and ineffective. She couldn't learn how to unblock herself within the org, and became paralyzed by stress.

We had multiple people to compare her against who did not suffer from any of these challenges. I am sure she can find a job that will work for her, as she was nice and did have successful moments, but a fresh start was clearly needed.