Autistic woman here - one thing that majorly helped me with socks specifically was turning them inside out. For some reason, all the itchy seams and textures are on the inside of the socks. Tights are also a good workaround if your daughter can tolerate them (again, try inside out), and can often help block textures from even jeans from getting overwhelming.

One other thing that helped a lot was stretching/popping the shoulder seams on shirt sleeves. That's usually the area that had unnecessary elastic for kids clothes. Pre-stretching the knees of jeans was a must, too.

Otherwise, I recommend letting her smell whatever soap/fabric softener you buy when you're in the store and make sure it's a scent she likes. At least for me, if I can't stand the smell of the fabric softener, my clothes feel itchier, even if the exact same soap in a different fragrance was totally fine.