I going to go with Frontier Fiber Optic. They won't run the cable under the house. I'm going to use Jeidus Patchcord SC/PC-SC/PC 9/125 3.0mm SM SX 30M Insertion Loss A o.26dB Return Loss A 36.9dB. The cable is 100 ft. Does anyone see a problem with this. I have never used fiber I always ran coaxial. The size of the fiber looks small.
The fiber itself inside the cable is even smaller than the cable. Most hair is about 10 times thicker than the fiber itself.
Key is most fiber is glass and is extremely fragile especially patch cords which are designed to be used in a protect area. If you were to wrap that cable around your finger it would break it internally.
The cable the ISP uses outdoor and underground is more protected but generally this is only sold as bulk fiber and putting ends on fiber requires special tools and training.
Just be very careful when you run and try to protect it so say someone or a animal under the house in the future does not snag it and break. Since I suspect it is not something you want to do again I would run flexible conduit under the house many times called "smurf" tube because a very popular brand is blue in color. You could then pull your fiber through that and it would likely never get damaged.