I don't mean this as flamebait but my pet theory is that showering and washing your hands is the 1800s version of wearing covid masks (except it stuck around as a permanent feature). It's more of a public safety thing you do for other people than for yourself and doing it twice a day is probably way excessive. It's probably closer to once every two days or less depending on how easily you generate body odor.
It's not just for health and safety, it's also to avoid inconveniencing others with body odors.
And there is a lot to be said about looking "good" too. I have very oily scalp (dry skin) and annoyingly thin and stiff hairs, if I don't shower daily, I'll look unpresentable pretty quickly. I wouldn't be dirty or unsafe but that's the image people would get...
I think you should have social status in your theory. Having access to hot water daily in sufficient quantities to fully bath yourself was not something most could afford, so it definitely made a very obvious class distinction at some point.
I'm pretty sure this is why people used a lot of perfume at some point; if you can't bathe to remove the stinks, you can try to cover it with a stronger and (hopefully) more pleasant smell.
But as much as I dislike body odor there is a lot to be said about strong perfumes. Some people find it reasonable to cast their odor of choices to a 2-3m perimeter around them; they might be worse because at least in their case we know for sure they had a choice...
It depends so heavily on lifestyle and climate. I really, really wish I lived somewhere cooler. Getting essentially 6 months of grueling summer just sucks for sweat. I often feel sticky and gross, because I am.
Tropical climates are extremely humid and you'll get sweaty just sitting indoors without air conditioning. As opposed to say, Europe, or even middle east/Australia.
On the positive side, water is abundant in tropical climates. My family of five showers 2-3 times a day, and the water bill comes down to ~$2/month.
