iPhone not charging past 75%

So since I updated my iPhone 11 Pro, it will not charge past 75% apart from the odd lucky day when it changes to 100 .. how can I change this!?

I have tried turning the “optimised battery” both on and off but it still only now and again charges to 100%

I understand this is because Apple don’t want phone at 100% but when I’m out at work from 7am - 6pm and my phone is running out of battery during the day and I’m unable to charge, this is a stupid new feature which doesn’t help at all !! I need my phone to charge to 100% when I DECIDE I want to charge my phone to 100% not when “the algorithm” decides too!!

How do I change my battery settings?! Please help!

[Edited by Moderator]