Just a tip, if you tap the icon of current mode(moon for me) it toggles, tap the text to bring up all the modes, if you want to turn on a different mode.

You can very easily turn it off with the control center (swipe down from top right of screen) toggle. You can also set certain apps/people to be able to contact you even when on. You basically have complete control of everything.

But you can turn it off with a switch, unless I’m missing something? Isn’t the control center toggle exactly what you want?

Rock Climbing/Bouldering. It’s great exercise, I throw in my earbuds, do my own thing, it’s a lot of fun. Don’t worry about being out of shape there are routes for all skill levels