Hi [Hiring Manager],
I’m so thankful for the opportunity to have interviewed with [Company]. I know that you all are going to find someone excellent for that role.
I really appreciated A, B, and C about the process. In particular, [this part of the process] helped me improve [skill or qualification related to role], and I can’t wait to put that into practice.
I’d love to stay connected with you as I continue looking for the right opportunity.
Have a great rest of your day!