Downgrade to iOS 10

Hello,

I have an iPhone 5S with iOS 11.2

It's unbelievable the change I have experienced updating the OS from iOS 10.3.3. With iOS 10 my iPhone was a first class phone; with iOS 11 it is a paperweight. Well I rectify, is a paperweight connected to a cable, because I have to recharge the battery a couple of times per day. That wasn't happening with iOS 10, I have waited for the version 11.2 just to see if it improves, but it is still the same.

Why can't I downgrade to iOS 10? Do I have to buy a new iPhone? At the moment I can't afford it. This is how Apple expects to keep the customers?

I know I am not the only one having these problems, so if you know the iOS 11 doesn't even work properly on a iPhone 7 (a phone 1 year old), why don't you let us choose the iOS version?

Just to be clear, I would like to downgrade my iPhone 5s to iOS 10.3.3, is that possible?

Thank you and I wait your response.

Regards,
Oscar Souto.