Toolbox

I picked up a 2022 3500 HD Denali a couple of weeks ago. I just got my new B&W hitch in today and it looks awesome! Haven't tried hooking it up to the trailer yet. Probably next week. Main question I have right now is I need a toolbox. My brother has a behind the wheel well pork chop box as well as an in front of the wheel well deep box. His biggest complaint about those tool boxes is that they are so wide that he cannot get a 4 by 8 sheet of plywood to lay flat. I've looked at some of the Cross bed tool boxes that have a very shallow lip to go over the bed sides behind the cab but I'm afraid that I still may hit it. Any suggestions would be awesome. I do want something large enough that I can fit my gooseneck kit in it as well as some basic tools, jumper cables, tie down straps, etc. I've thought about one of the flat boxes with drawers that would sit on the bed behind the hitch, just inside the tailgate, but I know nothing about them.

Lyle