For most visitors the real risks are not violent crime — they are overcharging, transport confusion, and being genuinely stuck when nobody around you speaks English. Dhaka is dense, loud and fast, and it rewards people who know it. Serious incidents involving foreign tourists are rare, but travelling with a local removes almost all of the day-to-day friction, and I plan routes around traffic, crowds and the hours when areas are quieter.
I will also tell you honestly when a plan is a bad idea — a protest route, a late night in the wrong area, a boat in the wrong weather. That is part of what you are paying for.