Gravy can be made from the meat juices and thickened with flour or as I prefer cornflour. Mix a couple of heaped teaspoons of flour with water in a cup to make a liquid and stir it as you pour it in to stop it going lumpy. If it needs a bit stronger flavour I then add browning or some gravy granules
Making sauces which are quick and easy to do seems to be a lost art for the under 40's where sauces can only come out of a jar.
How many people have and use a stockpot these days. I use mine regularly especially after a chicken roast with the stock being used to make lunchtime soups. I remove the fat by letting the stock cool down and skimming it off.
If you like eating good food, which I do, it has to be homemade or cooked by proper chefs at a restaurant.