The same treaties that define what are international waters also define universal jurisdiction for some crimes - every country is allowed to exercise their sovereignty against pirates for example. The list "just" needs to be expanded.

Lol, they don't even match consistently between Portuguese and Spanish which are much closer, even when the noun is literally the same (e.g.a água vs el água)

It takes a special kind of person to accept being punched in the head for a living.