First if you have a bad signal, you are going to have a draining battery.
Second, you don't have to disable processes that make Android devices what they are.
You can't just compare iPhone to Android in that way, that is comparing apples to oranges.
Just one minor thing and that makes a difference in battery, is widgets. Android has actual widgets, with info delivered to your home screen, fully functioning, iPhone doesn't do that. The widgets of iPhone are notifications.
How do you think iPhone operates with so little RAM? It doesn't have all the processes running because it doesn't do near the same as Android. Android is highly customizable, which is why Android users choose Android. If it is highly customizable, people are going to use different things. If you have something running that you don't use and you are already having battery issues, you can just disable what you aren't using.
Now my sister has an iPhone and she is connected to a charger all the time and when she isn't, she has a charging case she has to use a lot.
Neither is true for me. Her phone also does very little of what my phone does.
Trying to compare the Android and iPhone is like comparing a Toyota Corolla and a Sports car and saying the Toyota is better because it gets better gas mileage and your sports car should get the same gas milage and you shouldn't have to put more gas on it and should be able to use 10W 40 oil in the sports car that is much cheaper instead of having to use 5W 30 oil.
Yeah, they are both cars, but when you have a V6 or a V8 sports car and try to compare it to a Toyota, performance is quite different and they will never get the same gas mileage and having simply higher gas mileage doesn't always mean anything. You can't have a sports car and then expect it to run like a Toyota.
So, if you want a sports car and the gas mileage of a Toyota, there are things you have to change about how you drive the sports car.
If you want a high power Android and want a battery that last like an iPhone or even a Samsung Galaxy Core Prime, you are going to have to give up some of those functions.