Even if the Novus Ordo is intrinsically evil, receiving Holy Communion could represent a material, rather than formal, participation in the evil.  Material participation in evil can be permitted based on various circuмstances.  So, in a grave situation, such as danger of death, I do not see how it would be illicit to receive a doubtfully-valid Holy Communion that resulted from a Novus Ordo consecration.

cuм ex was partly abrogated with the promulgation of the 1917 CIC.

Clemens Maria, do you believe there is a Catholic Hierarchy today with Ordinary Jurisdiction? Ecclesia-vacantism is the denial of that. The Dimonds are ecclesia-vacantists. Even they don't deny there are a few episcopi vagantes here and there, https://en.wikipedia.org/wiki/Episcopus_vagans but valid Bishops alone are not enough. You need Papal Appointment to Office. Otherwise, Ordinary Jurisdiction cannot be transmitted.

As for the Cardinals/Roman Clergy, what is needed is incardination into the Roman Church. For that too, a Roman Pontiff is needed. https://en.wikipedia.org/wiki/Incardination_and_excardination

Your claim about me is incorrect. All the Popes from John XXIII to Benedict XVI who lived and died/resigned as universally accepted Popes are certainly Popes and will always be such. The Church has already ruled on their status infallibly by accepting not only their election as Popes, but also their death as Popes. Pope Francis' election was certainly valid. But Pope Francis may lose the pontificate at some point in the future, provided he proves manifestly obstinate after one or two admonitions from the Cardinals and Bishops. I didn't say Pope Francis has already lost his office, nor even that he would necessarily do so in the future. Reread my post carefully please, and don't impute to me something I didn't say. I only outlined the canonical process by which both (1) the fact of the heresy itself, as opposed to a lesser theological error, and (2) the fact of public pertinacity, as opposed to being ready to be corrected by the Church, must be established by the Bishops and the Cardinals.

61 year SVism hasn't taken of in 61 years. It's unlikely it'll take off even in the next 61. The scholars who wrote the letter believe all the Cardinals are real Cardinals and all the Ordinaries appointed by Pope Francis and his 5 predecessors are real Ordinaries. That's the advantage they have.