no, I can't agree with your conjecture. I have no difficulty whatsoever with Canon IV, but I disagree with you that it "condemns with anathema" baptism of desire. In fact, the canon specifically says, "or without the desire thereof".
Of course it says "or without the desire thereof" - but you have to admit that that is not the only thing it says.
When read as it is written, those words condemn with anathema those who say
justification is possible via faith alone - i.e. without the sacraments "or without the desire thereof".
If one cannot obtain
justification without the sacraments or without the desire thereof, how do you expect one can be saved without the sacraments or without the desire thereof?
Obtaining
the grace of justification "without the sacraments, or without the desire thereof", is obtaining
the grace of justification through faith alone - this is what Trent (the Church) condemns.
If this is confusing to you, it is because you are consistently taking those words out of context. Those words only are properly understood when read in context of the canon itself, which is all about the necessity of the sacraments for
salvation, as the words in opening sentence testify:
"If any one saith, that the sacraments of the New Law are not necessary unto salvation, but superfluous ... let him be anathema."