Since you otherwise raise good points, I don't want to see this seized on as nullifying the rest of your argument, and the stuff you got right ignored. [emoji14] Earlier in the battle, Luke took a glancing hit to the starboard-upper engine. "I'm hit, but it's not bad!" Later, the damaged stabilizer broke loose again during the trench run.
I'll admit, I've wondered over the years how much the Force/Obi-Wan was guiding things. Keeping Luke from being destroyed or crippled by that first hit? Deflecting his ship or the shot to damage a stabilizer, specifically? Cuz a damaged stabilizer would make the ship harder to fly straight and level, and probably make it harder to lock on to. Awfully providential damage, that...
ETA: Also, one thing you missed regarding Rey. After their escape from Haiku, when she and Finn are talking over each other, she says, of her flying experience, that she's "flown some ships, but never left the planet". So, per the film, she has demonstrably more experience than Luke who, while a (quite a good) pilot, yes, seems to have only flown the one light airspeeder.
ETA2: Finn is a Stormtrooper, not a janitor. He received top marks in training and was leader of his four-man training cadre. First Order Stormtroopers, after over a decade of training and preparation, weren't just sitting on benches waiting for the First Order to go public. They did grunt work. FN-2187 unfortunately got stuck with latrine duty. He was trained and skilled in all manner of melee and blaster weapons. There's semi-accepted stuff that lightsabers, while most effective in the hands of trained Force-wielders, are not unknown and others can be and have been trained in their use. Including an elite group of Stormtroopers by VADER. So I had no issue with his being able to do more than flail uselessly with one.
And no amount of training can ever prepare someone for actual combat. The reality of it was more than he could deal with, and it took him actually finding a cause he believed in and people he cared about and who cared about him for him to overcome that and rise to the occasion.
Plus, he wasn't a pilot, being the other thing being discussed. That was why he needed Poe.