Battery drain issue

My iPhone 11 pro max battery health has decreased from 99% to 93% in a day, before happening this my phone got glitched and I was unable to access it. On press the home button for a second screen went on and small loading circle appreared and then it kept happening same until I reboot the device. Once rebooted I check the battery health which showed 93%. What could be the reason for all this? kindly need assistance.