Loud fan noise and battery service warning

Hello, I have been using a Macbook Pro for about 1 year. Suddenly, my Mac started making loud fan noise and gave a battery service warning even though it had 96% battery health. I then made a service appointment with Apple Support and took it to the service center, where all tests were done and nothing was found to be wrong. I was told that this could be due to a data crack on the Mac caused by ICloud and that a new ICloud account could solve the problem. Has anyone encountered this problem and how can I solve it?