Speech can be analyzed in many ways and phonetics is one of them. The International Phonetics Association is active though well over 100 years old. The Alphabet which it maintains, like the load of dictionaries it has been used in, changes.
It can describe languages in minute detail. It can be used in a more general way like a script for an actor or a page of music for a flautist. In those dictionaries it can only provide a valid blueprint for ONE native accent at a time. That accent is not mine. Nor is it yours. Nor is it perfectly described. By useing an IPA description of a British accent we are not using a perfect model. Nor should we expect to find a dictionary that describes our accent. Language is personal and pronunciation is more so. Telling someone they speak badly can often be the same as saying they are too poor to be understood or that perhaps they and their family are not acceptable.
There is no wrong accent or right one.