iPhone 6splus battery life very bad with ios11

When I updated my 6s plus battery life to iOS 11, my battery life went down dramatically. I used to be able to use phone untill midnight and now I am lucky if I get through till 6 pm.

I am often below 20% by end of workday and this never happened before updated.

I know that battery life is an issue with iOS 11 on older phones and I have tried all the”fixes”.

My question is, do you thinks updates will eventually fix this or do I need to buy a new phone? I would hate to spend another thousand dollars because of software “improvements”.