I guess I’m just a little skeptical that Karl rahner understood the fathers better than Lefebvre did

The proof is that Karl Rahner was undoubtedly, unabashedly and proudly a Modernist.  If he had found even one Church Father who agreed with his V2-mindset, he would've exploited that quote to the nth degree.  It would've been repeated by every Modernist til they were blue in the face.  But they never found anything...

. . . we have to admit . . . that the testimony of the Fathers, with regard to the possibility of salvation for someone outside the Church, is very weak. Certainly even the ancient Church knew that the grace of God can be found also outside the Church and even before Faith. But the view that such divine grace can lead man to his final salvation without leading him first into the visible Church, is something, at any rate, which met with very little approval in the ancient Church. For, with reference to the optimistic views on the salvation of catechumens as found in many of the Fathers, it must be noted that such a candidate for baptism was regarded in some sense or other as already ‘Christianus,’ and also that certain Fathers, such as Gregory nαzιanzen and Gregory of Nyssa deny altogether the justifying power of love or of the desire for baptism. Hence it will be impossible to speak of a consensus dogmaticus in the early Church regarding the possibility of salvation for the non-baptized, and especially for someone who is not even a catechumen. In fact, even St. Augustine, in his last (anti-pelagian) period, no longer maintained the possibility of a baptism by desire.

In early 1962, with no prior warning, Rahner's superiors in the Society of Jesus told him that he was under Rome's pre-censorship, which meant that he could not publish or lecture without advance permission. The objections of the Roman authorities focused mainly on Rahner's views on the Eucharist and Mariology; however, the practical import of the pre-censorship decision was voided in November 1962 when, without any objection, John XXIII appointed Rahner a peritus (expert advisor) to the Second Vatican Council: Rahner had complete access to the council and numerous opportunities to share his thought with the participants. Rahner's influence at Vatican II was thus widespread, and he was subsequently chosen as one of seven theologians who would develop Lumen gentium, the dogmatic explication of the doctrine of the Church. The council's receptiveness towards other religious traditions may be linked to Rahner's notions of the renovation of the church, God's universal salvific revelation, and his desire to support and encourage the ecuмenical movement.

I reject such because i'm legally allowed to, since they aren't binding under pain of sin for me to attend/accept.  Even +Benedict said in 2007's motu that Quo Primum was still legally in effect and this law a) binds me to the Old rite, b) prevents me from attending any other rite, and c) disallows any new rites.  No post-V2 law has ever made the new mass obligatory, in any degree.

None of this gives you the right to outright reject Vatican II…

I outright reject V2, for the reasons adduced by +Vigano:

It had the form of an ecuмenical council, but not the purpose or substance.

V2 is not an ecuмenical council, regardless of all the bishops who attended.

That I cannot determine by perceiving with my senses and apprehending with my intellect that the public sin of heresy has occurred and that I must wait for the Church to make that judgment is nonsense.  That's like saying I have to wait for the weatherman to tell me that it's raining outside before I can make the judgment that it is.  God gave me faculties to use them.