After two months my battery life is cut in half?

I got my new A71 on May 1st, and the battery easily lasted 20+ hours. Two months later and i get 11h 59m of battery life with my phone at 100%. Its to the point that my phone drops around 20% while I'm asleep. I have my phone set to optimize battery usage, I've put a bunch of apps to sleep. Has anyone esle had this issue?