Disclaimer - I don't own Tolkien's Middle Earth. This is another reflection on Rings of Power, but this one was inspired by reading a few other stories which poked fun at the fact Elves are supposed to have long hair via the canon, but they don't in Rings of Power. Unless, of course, you're Gil-galad. or female. And yes, this is one of the lesser issues with the show, but still amusing what with the Days of Our Elf promotional material.
And of Short Hair
"What have you done to your hair?" Thranduil said, the disdain evident in his voice. "I thought you, being my son, would know better."
Legolas simply gave him a somewhat bemused look. "Isn't it trendy?"
"Trendy?" Thranduil glared. "What is this trendy supposed to mean?"
"I guess one might explain it as what is current fashion-wise."
"We aren't the race of Men where fashion trends change with each generation," Thranduil said, then paused. "And that wasn't how I wanted to put that."
"You mean to say we aren't the race of Men where our lives are short, and our attention spans are likewise short, so they preoccupy themselves with menial things such as fashion to emphasis their status in an ever-growing community, whereas each of us Elves knows our place."
"And you, Elfling, are a prince and should know your place," Thranduil said, his facial features contorting in a manner that amused Legolas. "And even the commoners among our people aren't—that."
"The short hair," Legolas said, still smirking. "If it makes anything better, this is the result of me being over-exuberant and in need of a healer because even as an Elf, I should know not to overestimate my abilities."
"No, that doesn't make things better!" Thranduil snapped. "That makes it worse."
"I think not cutting the other side to match would have made things even worse," Legolas retorted, not caring what his father thought, let alone how walking out at that moment would be perceived by the Elven king.
Note - Says Mark Twain, "An author should say what he is proposing to say, not merely come near it." Tolkien was a language professor; with every word he used carefully planned out and intentional, he consistently described the Elves in the books as having long hair with a few exceptions, such as illness and its ilk. He was also consistent in his illustrations of Elves. The argument that short hair is a possibility is based on the idea that Tolkien, of all writers, didn't "say what he was proposing to say" and "only merely came near it." And that's not Tolkien, language professor that he was, and he despised allegory, reading between the lines.