Ambience around 30 East 31st.

Don't know if this is close enough to your area of interest, but for a few years I used to live at 34th and 5th and it was not bad, except for crowds. It was very convenient to anywhere in the city and safe. This map suggests it is a fairly safe neighborhood as well: https://www.neighborhoodscout.com/ny/new-york/crime
K town not too far away, fun at night and great food

While it is commercial, it is safe and walkable. For streets at night, you have to experience it yourself as your preference may be different from others.

I walk around here every other week very early mornings when it's still dark and it gets worse as you walk East that time of day.