I’ve had fiber installed at two houses this year, and in both they worked with me to get the fiber, the ONT and the Ethernet exactly where I wanted them at no additional charge. At my old house, the fiber came in through the basement in the back, the fiber runs under the joists until it ends up under my office, and they ran Ethernet up to an outlet on the office wall. At the new house, it enters into my basement workshop, on the top shelf of a cabinet, where the ONT is and Ethernet goes to my router. There is plenty of extra fiber coiled above the drop ceiling for relocation.
It depends on the neighborhood. Where I live, all utilities are underground. At a former house, I had broadband coming from utility poles.