Hi Ioc164,
Thanks for visiting the Apple Support Communities. Let’s take a look at your iPhone 6s, we understand because battery life is important to us too. It’s always good to let about 1 or 2 days go by after updating to see how the battery life will be. Also, take a look at the iOS version, the current release is 14.7.1.
Thanks for the screenshot. You may already know, but just in case we’d like to share Maximizing Battery Life and Lifespan with you. It’s always a good resource to look over and make sure no settings have changed.
Take a look at About the battery usage on your iPhone, iPad, or iPod touch, the first section, “Check battery usage”. Looking at the Battery screen, if you scroll down, you will see a breakdown of the apps and how they are using the battery. Do you see any apps that have unusual battery usage? If so, you may want to try deleting and reinstalling a fresh copy of the app. If needed, see Delete apps on your iPhone, iPad, or iPod touch.
Reach backout if you still need help.
Take care!