I would very much disagree that it's the main beef.
Nothing good ever came out of not listening to people. The assumption that everyone is being dishonest with themselves and others, while its sometimes correct, is probably never justified.
The "main beef" with Rey is a lot of little things that add up to a very poorly written character. But as for the writing around making her heroic, one of the areas it's pretty easy to show that the writers treated a female character differently than a male character is that when Luke meets his mentors like Han and Obi Wan - older wiser figures that are supposed to guide him in his heroic journey - they put him in his place. And we the audience are made to understand that Luke needs to be put in his place, and that whatever his skills potential is, he's still a green and inexperienced kid in many ways. Luke gets flattened by sand people and needs rescuing. Luke gets flattened again by criminals in the cantina and again needs rescuing. Practically every time Luke opens his mouth Obi Wan is rolling his eyes and signaling to the audience (since Obi Wan has been shown as older and wiser) that Luke is being naive. And then we have the whole Han "Jumping through hyperspace isn't like dusting crops".
By contrast, when Rey is introduced to her mentors - Han (again) and Luke - she puts them in their place. She corrects and instructs them. Why? Presumably because the writers could not stand to have on screen a woman being corrected by a man about anything. However, this leads to absurdities like Rey showing up on the Millenium Falcon and correcting Han about his own ship.
Notice by contrast both Andor (in his own show, by Luthen) and Jyn Erso (in Rogue One, by K2S0) are put in their place earlier in various ways by more experienced mentors, without diminishing either character. In fact, Andor (in his own show) is allowed to be a bit of an idiot who, though hyper-competent in many ways, is still clearly learning his way through the world.
One of the many many problems with Rey as a character (which is just one of the many many problems with the sequels as movies) is that they vaguely seem to want to have a "golden trio" - the three friends working together to fix things. They seem to want to have an ensemble cast. But none of the characters actually have any sort of relationship with each other because the central character Rey doesn't need anyone. She's a much better character for a solo story, but the Star Wars feel typically is an ensemble cast. In the original trilogy, R2-D2 was the best tech, C3-P0 the best face man, Han the best rogue/shot, Luke the best pilot/swordsman, Leia the best leader/diplomat, etc. and everyone got to have their own moments to shine even if they were the comic relief. Compare this with JarJar Binks that is never really useful as a party member, or with Rey who doesn't need a party for anything because she's a better mechanic than Han, better warrior than everyone, better rogue than everyone, and so forth. It doesn't make for a good dynamic in the story.
It's not sexist to think that Rey is a badly written character, that Jyn Erso is less badly written, and that say that Ellen Ripley (of Alien and Aliens) or Sarah Connor (of T2: Judgement Day) are much better written characters. As soon as you start pulling, "You're just a SEXIST. You just can't handle strong women" for not liking Rey to someone that loves Ellen Ripley or Sarah Connor, you are the one that is a sexist.