You’ve mentioned quite a few things in this post, making it hard to discern what the exact problem is. To get the best help you’d need to define a very clear checklist of features that you need, and then what problem is preventing you from achieving them.
I can point you to this short overview of a topdown camera here:
Beginner Micro tutorial : Simple Top down camera with screen edge panning, two aim styles - Programming & Scripting / Blueprint - Unreal Engine Forums
If you have any specific questions feel free to ask.