"I endorse the idea that governments should be allowed to severely tax all pornography, if they're not already."

I do not.
Pornography is harmful to the reputation of those depicted. Taxing pornography for the benefit of general use of taxpayer makes the taxpayers live off immoral earnings.

What I endorse is impounding significant parts of pornography proceeds for appreciable time. And ensure that the impounded profits are eventually returned to the models. Not spent by taxmen, and not captured by pimps.

If immediate profits are low, then it deters many from trying... which is also a desirable result. You want to protect girls from becoming cheap whores. So don´t forbid them from becoming whores at all - allow only expensive whores. Either they get a good reward, or they get to keep their honour. Both of which are better than being cheap whores.