...gravies unknown today...
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I come from two lines of Eastern European immigrants. The secret of those gravies is to save/freeze every scrap of meat fat, including the stuff that solidifies on the top of pan juices, along with all those pan juices and you have the true gold of cooking.
If you have those, you need some flour, seasoning (not much as the drippings are intense) and ANY liquid (Red Eye Gravy is just using coffee instead of broth for gravy).
A bag for bones and a bag for vegetable scraps and you now can make soups and stews with more flavor than any MSG-enhanced commercial product.
I met a feminist once who said that “Ladies, gravy is not a beverage”, there is nothing wrong with a man having a couple of cups of gravy during a big meal.
A great tip from the past!