If you think your apps are still draining your battery, even as you're closing them properly after use or force-stopping them, you might be running an outdated version of the OS. Make sure you've updated to the latest version by going to "Settings -> System -> System update."
With the advent of Android 10, Google has introduced various power management features that control how much power apps end up consuming. This is why, if an Android 10 or above update is available for your device, it should be installed right away.