Not sure that trying to root a whole big branch would work. Just the tip with only a few leaves probably better. Try posting photos of it, you might get more responses to your question :)

I'd like to see a photo too.

I also doubt that it's possible to root a whole branch because it will be hard to get enough water to support so much living tissue all the way up the branch without roots to take it up, even if you removed some leaves.

That being said, it should be easy to root either the end of the branch or a segment of it by simply sticking it in soil and spritzing the soil to keep it moist (not wet) until you see some new growth to indicate that there are roots, at which point you can start to water normally . Just be sure to get at least three nodes under the soil and you'll get roots quickly. You shouldn't need rooting hormone; ficuses root pretty easily, especially this time of year.

I don't know how long a piece of the branch you can root, but maybe someone else will be able to tell us.

Sure it will. Bigger is easier to form root. The reason people make small cuts is to create more plants. More plants = more money, if you want to sell them. I suggest you cut it to 2 - 4 pieces, with at least 3 nodes each. Just in case you fail with one, another have chance to survive.

Gudang, have you ever rooted a five foot branch?

Yeah. I just rooting 2 meters long arm size fiddle leaf fig. In fact, that is the way we plant trees along the street at rural area using any branches available around. 2 meters or more is necessary since less than 2 meters, goat or cow will eat the leaves.

Lifting water upward almost need no energy, and plant able to do it even without root. I already explain that somewhere on other post, on thread about vitamin maybe.

Wow, I'd never heard of that before.

Yeah, maybe not common in 4 seasons countries since it's hard to bring 2-3 meters stem inside house to prevent frost damage.