If we're in the EU our laws are inferior and EU law is supreme. If we're outside the EU then our laws are supreme. Do you understand that point?
Yes, but it's not true. We accept the supremacy of international law on a host of issues; when we sign agreements with other countries we - like most developed nations - accept that this are binding agreements on us. Leaving the EU may (or may not, depending on the post-Brexit deal) cause us not to be bound by some EU laws but it will not make us suddenly supreme in matters of international law.
Also, EU laws are our laws. We're part of the EU and we play a big role in EU law making. If we end up with some "Norway" arrangement then we really will be bound by laws other people are making.