Update or Get Rid of Your Apps
Sometimes, your iPhone is fine, but it’s the apps you’re using that are causing trouble.
For instance, if an app hasn’t been updated to the latest iOS software update, it might stutter for no reason. Moreover, as you can probably tell, first-party apps work better with iPhones than third-party apps.
So, if you have a faulty app that’s slowing down your iPhone, the best solution is to get rid of it. Apple already has its own alternatives for some of the most popular apps on the App Store. Using those instead might make your iPhone run faster again. Not to mention that deleting apps will also clear up some storage, which will also help with performance.