It really depends.
Scale of bomb
Design of bomb.
Distance from epicenter
Ground explosion or atmospheric
Prevailing winds
City construction
Etc, etc.
It's nowhere near as simple as we've been taught.
I've looked at the bomb simulator linked above, and for me and my city, and where I live, prevailing winds, etc, only the two largest warheads would have direct effect on me, and fallout isn't a concern for the rest (distance and prevailing winds).
Now after that, it would surely be a complete shit show. I'd likely have no water (or maybe I would, this suburb isnt tied to the city). Power would certainly be an issue, as would telephone/cell, radio would be problematic for a short while. Food would be a problem, of course.
Agreed.
A great alternative that has selective Sync is Resilio. I find it to be heavy on my phone (because I have a massive media library and it keeps the database/index in ram).
But it lets me browse my media share anywhere, anytime (from the phone), and have it sync files to the phone as needed.
For everything else I use Syncthing-Fork on the phone, and SyncTrayzor on Windows.