How do I improve battery life on my iPhone 13?

Ive had my iPhone 13 since 2023 and the battery has started to be so bad on it that I can’t even go outside without worrying it will die. I’m honestly considering switching phone brands because I’ve heard things like apple doesn’t build products that last and that’s really what I need. I’ve keep it updated, I’ve kept my brightness down, I’ve uninstalled things that took up a lot of storage, I’ve put it on low power mode and nothing seems to help.

[Re-Titled by Moderator]