The knot is non-SI but perfectly metric and actually makes sense as a nautical mile is exactly one degree meridian. kn also doesn't clash with kN, Newtons are always written with capital N. Capitalisation generally matters. No standard abbreviation exists for nautical miles but definitely don't use nm because ~~newton~~nano metres.

That is, if you take all those colonial units out of there suddenly you're left with SI units and things that work well with SI units.

Oh and a pint is 500ml, a pound is 500g, a hundredweight is 50kg (because 100 pound), and a teaspoon is rather approximate because everyone outside of North America will use an actual spoon you stir tea with. The important part is not the precise amount but distinguishing it from "a pinch" etc. I guess by extension ounces should be 25ml and 25g. While we're at it: An inch is 25mm, and a foot an even 1/3rd of a metre while a yard is exactly one metre.

Did you know that a Newton metre is about exactly one chocolate bar metre? The work it takes to lift it in about standard gravity, that is. Very intuitive.

t for ton is a quirk in SI, you can use Mg if you want. There's also other SI-adjacent strangeness such as the hectare, which is one hecto-are: While SI has meters for length and litres for volume somehow the are isn't official for area.