Well, R&R has a tendency to resolve itself one way or another.  We've seen this process for years.  It's a very tenuous place to be.

If the Conciliar hierarchy is legitimate, then the Catholic sensibility draws one toward submission to them, toward submission to the Vicar of Christ.

If one CANNOT submit to them, then the Catholic sensibility draws one toward concluding that they are illegitimate.

What has always distinguished Catholics from those outside the Church is the submission to the teaching authority of the Church.  That is THE uniquely Catholic sensibility.  So this recognition of their teaching authority and, at the same time, refusal to submit ... runs counter to the deepest Catholic instincts, and it tends to resolve itself one way or the other.

The pioneer Catholics who kept the faith in the 60s never concluded such a thing, because prior to V2, that was not the Catholic thing to do, Catholics back then never even considered such a thing. Deciding the pope to be illegitimate was authored by a priest, Fr. (now bishop) Sanborn, and that idea did not really surface till around the mid 70s, it really only started to grow in popularity in the mid 80s.

But prior to that, Catholic sensibility during the infancy of the revolution was to keep and stay true to the only faith they ever knew, and that the happenings within the Church contrary to that faith were to be avoided. The Catholic sensibilities said that worrying about the pope's legitimacy would have only unnecessarily been, and still is, cause for greater confusion and division among those striving to keep the faith. How very right they were - and still are.

But understand if you can that Catholic sensibility does not now, nor has it ever drawn any priest or lay person toward concluding that they are illegitimate, rather, I would say like the pioneering Catholics, that venturing into that arena is due to a lack of Catholic sensibility. It may be some other sensibility, but it's not Catholic sensibility.