Maybe try the 'non-gentle' way first.
I think there is general agreement that gentle explanations + understanding combined with fixed boundaries = a good method.
But, I think some parents get these the wrong way around, and that isn't their fault at all. It is rarely explained well to parents.
But in short, the boundaries and firm parts always come first, not the gentle explanations. You can't have the gentle explanations and understanding, if the child doesn't understand the boundaries. Priority one is letting the child know where they stand, and making their world clear, safe and understandable - that means they know who is in charge, and they know the rules and the consequences.
Once that is established, you can then have plenty of great discussions, gentle, explanatory, lots of positive things - but you need the non-gentle boundaries and discipline first.
Doing it the other way around leads to frustrated parents who feel like they have done the right thing, but have an out of control child. Trying to reason with and explain things to a child who doesn't understand consequences and boundaries rarely goes will - especially with wilder boys.
It is the same in classrooms. If you have a class of students that understand and work within clear rules and boundaries, you can explore great things, give them freedom, explain things, discuss things in a meaningful way etc. But if you have an out of control class with no respect for authority - no amount of quiet chats will snap them out of it, they will just laugh in your face, shout over you and carry on.
So simply set very clear and consistent and firm boundaries - and wait out all of the shouting and screaming, and never give in to it. When he can understand that - then you are in a place where you can start to reason and have calm gentle understanding based approaches.