I don’t use Notability but I have Catalina on a 2019 MBP and have the same issues as being described here.
Store says the computer is fine and sending it in would either result in them saying no issues found or a good faith battery replacement.
normally you’d never hear the fan run. Now you do and it continues to run and almost never stops. Even runs after I boot it up and go to desktop.
it dropped today from 80ish% to 5% in an instant. First time it did that since upgrading.
not an app issue, it’s a Catalina issue. Too focused on new stuff, and caused many more problems, just like iOS. Poor quality control especially for a brand new computer with Catalina
checked activity monitor and nothing shows as abnormal on any aspect.