Football basically requires 2 camera bodies and 2 lenses.
One body and lens for the telephoto work, the second body and lens for the close in action.
Both indoor action and nighttime field sports require camera bodies that have good high ISO performance and lenses that can open to a wide aperture.
Because of the inverse square law of light and light spread, strobed (flash, or speedlight) lighting is pretty much limited to close in action.
There are some speedlight attachments, like the Better Beamer that help the light spread issue somewhat:
Visual Echoes FX3 Better Beamer Flash Extender for Use FX3 B&H but doesn't address the limitations imposed by the inverse square law.
Shooting sports well requires having a pretty good technical understanding of how the camera, lens, and light work. Because of the lighting conditions and distances involved, shooting sports requires some of the more expensive photography gear. (the Sigma 120-300 f/2.8 lens mentioned above is a $3200 lens, new. I use a Nikon 200-400 f/4 lens that is $5670, new, though I was able to buy the lens used for just $4000, an unusally low price.
The inverse square law is a physical law of nature. The amount of light that reaches a subject is a function of distance, and it is a square function. If the subject (or you) is moved to twice as far away, only 1/4th as much light reaches the subject. If the distance is again doubled, only 1/16th (the square of 1/4) of the light reaches the subject.