Your iPhone is behaving weirdly, apps non responding, phone slow … Basically you want to throw it away ? Before dumping your phone, did you try to “soft reset” your iPhone ? No ? Try it and it might help you.
Be aware that the soft reset doesn’t delete any content, it will just clear your iPhone memory and restart from a clean slate.
You need 2 fingers to soft reset your phone: 1 on the home button and 1 on the sleep button and you keep pushing both until you see a black screen … Keep pushing until you see the apple on the black background … Now you can rest your fingers. You just soft-reset your iPhone.
At the appleStore, they told me to do it at least once a week.
PS: it works for the iPad too 😉