Yes, of course, the Sacrament of Baptism is absolutely necessary by a necessity of means for salvation.
But theologians like St. Robert Bellarmine held that the Sacrament was necessary at least in voto.
Now, modern BoDers mostly hold that the Sacrament is not absolutely necessary by a necessity of means for salvation, but effectively reduce it to necessary by necessity of precept. And I have excoriated them for that. It is in fact heretical. Others basically have a Pelagian view where they somehow ... in muddled thoughts ... imply that people can merit salvation or somehow deserve salvation.
To make it scholastic, one of these theologians might argue according to this distinction:
Yes, the Sacrament of Baptism is absolutely necessary for salvation.
1) that it is absolutely necessary for salvation saltem in voto, concedo
2) that it is absolutely necessary for salvation in re, nego
Now, I do not agree with this distinction and hold that it is necessary for salvation in re, but I cannot condemn it as a heretical rejection of Trent, not when it was held by someone like St. Robert Bellarmine.