One of the more cumbersome things about working in Pro is that it is very difficult to actually take advantage of multiple monitors/windows. When you drag a view out, nothing comes with it -- ribbon, QAT, panes, nothing. I need not explain why this is clunky and inefficient in practice -- try working with multiple maps or layouts this way and you'll see. The most frustrating example is the contents pane, which can only exist once in an open project and constantly switches based on which view is selected. You can tear that out, too, but then it's floating, and you probably want a TOC in your main view, too, if you're multitasking.
One sensible way to reduce this frustration and constant mouse travel to another screen to access commands detached from your floating window would be providing a way to dock panes inside a view so that they go along for the ride to your other screen. This would also require the ability to have duplicate panes open -- eg. I am going to want a contents pane for each floating view, and perhaps others like symbology, element, etc. Each pane, then, would be associated with that view and reduce the amount of switching back and forth providing better muscle memory and much faster workflows. Perhaps floating windows can somehow be distinguished from second instances, since at that point they may look similar and I can imagine scenarios where I have both floating views and multiple projects open.
Working in ArcMap, by virtue of the fact that it's not project-based, didn't really have this problem since you'd just have two or more instances running. But if the advantage of Pro and ArcMap's predecessors is the project-oriented architecture, in theory, it should be easier to multitask within one instance, not harder.
Similar idea for including a ribbon & QAT with floaters: Include ribbon, QAT with floating views - Esri Community
