I think the most important piece of equipment we have in our arsenal is our camera. We have slowly, but surely, upgraded our camera and lenses as our skill and budget have increased and are extremely happy with our Nikon D850 set up, especially with the Sigma Art Series 85mm glass. For travel/street photography we are using the Nikon 50mm f/1.8G, which is an amazingly versatile nifty fifty that can carry over into the studio if your budget is a little tighter. Check out the full specs on the Nikon page and this awesome review on Digital Photography Review to learn more.Click the image to be redirected to Amazon for more details.
I also highly recommend getting the RAVPower USB Battery Charger Set for easy charging and the additional bonus of having 2 spare batteries for those longer shoots.