Honestly the budget you have will allow you to get just about anything without going extreme that is.
The problem is that most GPUs simply can't be bought right now and while I would typically tell someone to build there own, the best chance you have right now of getting top parts is to buy a complete system.
If you have a Micro Center in your city I would start there. They could really help you figure out if you really want to build your own or if one of their house models will fit the bill. Even with those they still have last gen processors but do have current gen GPUs in some models going for about $1800. Their house brand is Power Spec and they are built as if you bought the components and put it together yourself. No proprietary stuff as with HP or Dell that you have to go back to them if parts fail. Unfortunately they don't sell most these systems online only in store so if you don't have a location, you are out of luck.
If you have any retail computer store in your town I would call them, tell them your budget and that you need help. I am sure they can make suggestions that will help just know that some of the best options right now are very hard to come by.
If you could wait a few months you would likely have a lot more to choose from as things are just selling the second they hit the shelves and individual components.
