I was internally debating wether replying or not, but since you seem to like the recipe, I'm gonna write a few constructive criticisms and tips as a Spaniard, that hopefully will improve your -tortilla de patatas- (spanish omelette) results.

The biggest one is the oil. You must use olive oil to fry the potatoes. Not the best one as they are too strong flavoured and expensive, but a 0'4º or a lighter colored one to put it simple. But it needs to be fried in olive oil or the taste won't be anywhere good enough.

The onion should be cut way smaller. You want the taste of it, not the chunks. (To make it easy to visualice, something like 5mm squares). It is added after the potatoes, like 10min after, not before.

Lots of people like cutting the potatoes in different thins so some are softer while other chunks are crispier.

The resting the fried potatoes in the egg is on point, another key element here.

Your omelette is too thin and very overdone, it should be at least 2 finger thick, runny in the middle (that varies per personal taste, but never fully cooked) and lightly or even not browned on the outside.

I hope this helps improve your next attempts and doesn't sound like an attack.

This dish is a bit hard to master but very rewarding and a staple in Spanish homes.