I just got this a7c ii and i am so lost. I want to take photos of people and buildings in nyc next week but i dont get the lens stuff at all. My budget is like 600 bucks tops because the camera already cost a fortune.

I was thinking maybe the 35mm one because people said it fits more in the frame? But then I saw a video saying 50mm is better for the blurry background thing and now im just annoyed because i dont want to carry a huge heavy thing around. Why are some so much bigger than others if they do the same thing?? Is there a small one that isnt gonna make me look like a total tourist? What do i even buy...