I’m essentially with you on all of the above; except for the cold shower bit. Are you kidding?
I remember when cold showers were advised as a way for males to curb their sexual desire. It didn’t work with that. I’m skeptical about whether it holds any real value for most of us.
Like the hairshirt or other self-tortures that earlier Christians used to “prove” how much “holier than thou” they were — clinging to the assumption that to suffer is to be closer to God almighty — advice that focuses on the physically hard and uncomfortable for its own sake is that which I tend to disregard.