ios update

Usually once the new version settles down and most of the bugs get ironed out, it works better than the previous. iOS 13 is now at 13.3.1, so ample ironing has occurred.

Note that 13 did introduce quite a few new ways of doing things, so it will take a bit to get used to.

If you plan to do the update Over The Air, you'll need about 8-10GB free space in the phone and a reliable and speedy Wi-Fi access. The installer is rather large and needs to be verified and unpacked before use. If you do it with a computer and iTunes, those requirements will be less.

No, updates are meant to optimize and improve the experience of all the iPhones that are supported.

Make sure that your battery is in good shape. Go to Settings>Battery>Battery Health. If your battery is at 80% or lower, get it replaced. It will make a huge difference.