Problem is that my business is in VA, and I'm now subject to complying with taxing authorities in, say, California, where I don't have representation or a physical presence. It is unconstitutional in principle.
That you pay taxes for engaging in interstate commerce is in no way, in practice or principle, unconstitutional. Please, rid yourself of the notion that taxation without representation applies to interstate commerce. It does not.
The founders worked the commerce issue(s) out after learning the Articles of Confederation's approach was woefully inadequate for the establishment and governance of a nation. There is a very long legislative and juridical history you can dive into to fully understand exactly how the commerce powers have been worked out over the last couple hundred years.
It is not "unconstitutional in principle" for Congress to regulate interstate commerce in general, nor is it "unconstitutional in principle" for it to do so in a way which permits States to tax foreign businesses selling into the State the same way as local businesses selling in the State in particular.
Unless "unconstitutional in principle" is just a fancy way of saying "something newbie12 doesn't like".