You cannot smoke at Tel Aviv Ben Gurion Airport. All smoking areas have been closed in 2020. Passengers flying to Ben Gurion will not be able to smoke inside the building.
There is the possibility to smoke outside the terminal buildings. That may be a solution when you are on a long layover. You will have to pass through security on the way back in. Take this into account when going outside.
Strangely, Tel Aviv Airport is segmented into terminal 1 and 3. There is no terminal 2.