Which USB plug is 3.1?

My wife's iMac has both USB 3.0 and USB 3.1. I'd like to use 3.1 to recharge her iPad but I don't know which of her USB plugs are which.

We have a bunch of those little cubical Apple USB power plugs, but my eyes can't read how powerful they are. I expect they're less powerful than the two Apple power plugs with the slide-off plugs. One I can barely read has 10w, and the other has 12w. I also have a Conido 3-in-1 charging stand, which seems to recharge faster than my iMac that only has USB 3.0. But I don't know how powerful it is. Her iPad doesn't seem to want to charge hardly at all when plugged into those power plugs.

As soon as we can hold all 4 models of the iPhone 12, we're going to upgrade my wife's iPhone, probably waiting until Christmas to get her a new recharging stand. What power should I get for a magsafe charger?

And which plugs on her iMac are USB 3.1?