So, yes, the fact that the SACRAMENT of Baptism is necessary for salvation, that's dogma.
Now, the non-heretical articulations of BoD, those which don't say stuff like how you can be saved WITHOUT the Sacrament, or that there are "substitutes" for the Sacrament ... the few non-heretical formulations you have out there, such as that of St. Robert Bellarmine where Catechumens can be saved not without the Sacrament, but, rather, receiving it "in voto".
Even in BoD, they have to claim that the Sacrament was the CAUSE of justification / salvation, the instrumental cause, as Trent teaches about it. That's what "necessary" (by necessity of means) indicates, i.e. that there was a CAUSA SINE QUA NON (a cause without which it could not take place).
In other words, they have to say that it was the Sacrament that profitted them unto salvation ... except Florence rules this out, stating clearly that for those who are not in the BODY of the Church, the Sacraments cannot profit them unto salvation, and one does not become united to the body of the Church (i.e. in the unity of the body of the Church) until the Sacrament of Baptism.
See, this actually undercuts even Msgr. Fenton's desperation attempt to claim that those saved by BoD can be IN the Body even if they are not OF the Body. Well, the expression "in the unity of" precludes MERELY being IN the Body (and not part of it) but requires being UNITED to it, which only happens during the Sacrament of Baptism.
Were it not for the fact that the condemnation is not explicit, and requires a bit of reasoning, Florence render BoD heretical.
We await the restoration of the Church to put the final condemnation on this error.
Now, I believe that God permitted this error to go uncondemned and to fester because ... VATICAN II COULD NOT HAVE HAPPENED WITHOUT BOD. Without "BoD", there's absolutely nothing that would have permitted people to circuмvent EENS dogma and to invent the new ecclesiology which is foundational to all the Vatican II errors.
But God wanted this crisis to happen as a test of faith ... and, sadly, many are failing the test, even among Trad Catholics.
Now, God will not damn those who in good faith believe the Church taught BoD, and it's not been condemned with sufficient clarity ... but Vatican II had to happen for a broader reason.
See, before Vatican II, Catholics didn't really have to exercise their faith. They could "identify" the Church ... as long as they were literate, and could read the sign above the door that said "Catholic Church", and the only "marks" of the Church they needed was the sign marking the location of the any given Catholic Church building.
But now that the Conciliar Church has eclipsed and usurped the True Church, that doesn't work, so people need to actually "work", i.e. exercise their faith, to find the True Church, looking for the actual Marks of the Church. Those with weak, little, or no faith just lazily say "hey, there's a guy in white cassock, so that's the Church".