Will this help with the battery life and how slow phone is now??

Ever since I have dated my phone, it’s runs slow, battery life is gone, I’ve turned my apps off, cut down the brightness. Still no help. My phone now freezes. The option of just turning the phone around (long ways) it stays that way for it least a couple of minutes. You can’t shake it back to normal screen. I don’t like these updates, I think they were made for the newer phones, 7 and up and not made for my phone which is a 6plus. So now the iPhone 6 Plus is out dated in the technology world? If that’s the case I’ll go to a different phone with not so many hassles from updates. Doing my research that’s for sure.