The key to a great paella is great stock. If you use canned/boxed stock, which is basically dirty water, surprise surprise, your paella will taste like dirty water. Well, maybe not that bad, but certainly not all that good either. If you make a stock from scratch -- roast meat, bones & veggies for caramelization, then throw everything into a pot of water & simmer for hours -- your paella absorbs all that rich, delicious broth ¡una paella como Dios manda!
I'm not familiar with the Puerto Rican version of paella (btw, we Filipinos have our own take as well). At what point do you add the rice? If you simmer the rice for 2 hours, doesn't it get overcooked & mushy?
The original Valencian recipe does indeed take hours to make, if you make your own stock. I've watched a few YT videos by Valencian paella masters, and the recipe @jsn102 posted is pretty close. The only discrepancy is that chorizo or spicy sausage is considered a no-no because the flavor is too strong and overwhelms the yummy goodness of the broth.
For the record, I tried to make paella once. Eek, total disaster! But that was pre-YT. Watching those Valencian maestros go through the recipe step-by-step reduced the intimidation factor.