Disappointing battery life

I'm really disappointed with the battery life and inaccurate estimations on this so-called "flagship" phone. Even after multiple charge cycles, the battery readings are way off. My phone barely lasts 4-5 hours before needing a full recharge, and I can never get through a full day without plugging it in at least once.

As shown in my screenshot, the battery usage percentages don’t even add up correctly—apps that supposedly drained over 80% of my battery barely total 40% in the stats. Plus, the phone claims the last 20% will last another 4 hours, but in reality, it dies in 30 minutes.

I have battery optimization enabled, and while I’m not exactly conservative with apps, isn’t that what this phone is built for? Reviewers claim 10+ hours of screen time and say they can't kill the battery even if they try—but my experience is nothing like that.

Can anyone relate or have any tips?