If you still want dualsport find a used KLR and keep the cost under 4k, you'll be set for a long time to come.
If you don't care about dual sport hard to beat a FZ6 of SV650 for easy and cheap road miles. I wouldn't bother with anything bigger.
If I was going to buy a commuter (which I am not) I'd probably do a FZ6.
12 Yamaha Super T
11 HD Ultra Limited Sunglo Cherry Red & Merlot