Have you tried adding softener to the wash? I don’t use softener, but maybe it would work? I know when I stay at peoples houses who use it the towels seem very soft. I hate that, because the towels seem to not absorb water as well, but it might be a good thing when it comes to your sweatshirts. Another idea is turning your sweatshirts inside out when you dry them and using a dryer sheet in the dryer.