No you can also try a factory reset :)

My Sony Experia E4 had its functionality removed because of Google's stance on Android KitKat.

As in locking every KitKat user from installing most apps even though they were usable in the past. This is problematic as one of my most used apps is a banking application.

And unfortunately there are no ROMs that are compatible with my E4 so flashing wasn't an option. I was forced to purchase a (used) phone running a more recent version of Android so that I can use a dang application.

Yeah I was going to comment on that. I have several PCs (one desktop and several laptops) which are like 10-15 years old, at least. And they still seem to work quite ok.

Sure sometimes maintenance may be needed, like one's internal hard drive got fried, on my main gaming laptop I changed the fans as one of them started becoming noisy (in a broken way), and the battery which keeps clock in time during shutdowns needs to be replaced sometime too... but overall, if a PC (laptop or desktop) dies on me before it turns 10 years old, I am disappointed.

Dealer's choice. It definitely sounds like your battery is the fault. A new battery will outlast the next-to-fail piece of the hardware configuration, and batteries are among the most expensive single components.
Silicon is a layered medium.

For simplicity, think of a circuit with ten layers, and one fails. Then nine layers are carrying 11% more charge, until another fails, when the remaining eight are 20% over voltage, etc. (in this simplified example), as each layer fails faster since it is under progressively more load.

Hence once a component starts to fail, its demise will hasten with each cascade.

Why do you need to do your banking on a mobile device? You have a laptop or desktop, right?

Thanks for the comment, but, what the hell are you talking about?? Laptop or Mobile? Because, no, just no!

The only thing i can think of where that process might possibly apply is with the RAM, but even then, NO, because RAM tends to error out as soon as it starts to fail. Because Hardware is generally an all or nothing proposition, there is no place for a cascade failure slowly over time (except possibly a motherboard). Software is a different story though!

Silicon. Silicon chips (i.e., RAM, CPU, GPU, soundcard-on-a-chip, you-name-it-chips), are made in layers: multiple wafers of silicon semiconductors. Software (unless it updates itself in memory, and then just reboot it) is actually more stable, since it always has the same code (when instantiated).

Silicon chips admittedly look like something you would expect to be very fragile and prone to failure, but surprisingly no, they are exceedingly resilient and reliable inventions.
But there is one place where silicon chips are a total fuckup and should never have been used - in car engines! !!! So now mechanics have lost the ability to diagnose problems, because they are used to asking the computer, and if the computer doesn't know, the mechanic scratches his head and the "um arrs" start coming - Gawd i hate that sound ^%#$$^

Software is more stable than hardware?? Hahahahahahahahahaha

I pretty much stick with lg now, they cause me less issues out of any phones ive had. most problems I have are because of android. it's become so damn bloated and more intrusive than ever.

Isnt Android on LG??

Taking my comment out of context is amusing, yes. But, within the context, it is still true (however funny).
Software includes PROM instructions, after all; the stuff that boots low-level hardware. Capice?