Sacrilege, I don’t shower. Mostly out of ignorance though because I don’t know the full details. Growing up, my best friend’s family (much more frum than mine and very halachic) all showered on Yom Tov. They knew the halachic details.
Doesn’t R’ Moshe say that you shouldn’t use a shabbos clock to turn on air conditioners? And possibly other things?
And if your Rav says showering by doing XYZ is kosher, then why should someone be machmir? Because you don’t agree? Should I not cut anything on Shabbos because I may end up cutting things too fine? There is a reason we follow our rabbonim. They tell us how to apply halacha to our lives. If they give us the details on HOW to shower, why shouldn’t you shower?