I have a set of bath towels (extra-large, bath "sheets") that I routinely wash in hot in the Neptune 7500. That means over 125F. I can squeeze in five such, no more than that, or it has trouble spinning.
They seemed to be getting a bit rough, although the water here is generally considered to be on the soft side. I did a load of five with a cup of distilled vinegar, 15 minute wash, Not surprisingly, there was a bit of sudsing. Not a lot, but definitely visible. No rinse or spin, just drain. Then I repeated the hot cycle with a cup of baking soda. Just a drain, no spin. After that I washed them with the usual HE liquid, and no fabric softener.
At the end, after tumble drying they *seemed* to be a bit softer than those I hadn't washed, but the difference was quite slight.
YMMV