On 2024-08-28 Rob Dyck wrote:
The phone was manufactured in the spring of 2017, I bought it in
Ya, by 7 years most phones will have batteries that are on a steep decline in terms of battery life each day.
Your app batt usage chart looks pretty normal, comparing it to mine right now. I don't use gmail, though. But if you were hammering gmail during that time, it's not outside the realm of normality.
Adam has the right idea: you can replace the battery. Watch out, though, lots of the "kiosk" places will just give you a used one they have around which may not be any better than the original. Maybe stress you want "new" only, and ask to keep the packaging.
However, also consider that you aren't getting any sec updates on the OS, and that could leave open security holes. Which leads us full circle back to your original thought that you might be hacked/virused -- better odds of that if your OS hasn't been updated in years.
However, my money is on the battery. Note: a lot of new devices (all?) have a feature to prolong battery longevity by only charging to 80% (if enabled). If I got a new device tomorrow I'd totally have that on unless I'm going traveling or something.