There isn’t a single right answer here: 35mm and 50mm are both strong choices, and the best one depends on how you like to frame.

On full frame, 35mm is generally the more versatile walkaround focal length for street work because it makes full-body shots and environmental portraits easier in tighter spaces. If you want one lens to carry everywhere, 35mm is often the safer choice.

A 50mm can work well for portraits and some full-body shots, but it won’t truly replace 35mm if you often want to include more surroundings. It gives a tighter perspective and usually needs more working distance.

Based on the sample style you described, some photographers would actually prefer 85mm for stronger subject isolation and flattering portrait rendering, especially outdoors where you have room to step back. But 85mm is less flexible as a single do-everything street lens.

So if you can only buy one, pick 35mm for versatility and walkaround use; pick 50mm only if you strongly prefer a tighter portrait-oriented look. If your priority is maximum background blur and classic fashion separation, consider whether an 85mm fits your shooting style better.