What is not being said and needs to be said is there are 2 Thuc lines.  Bishop Moises Carmona and Bishop Guerard des Lauriers.  They are different.

The First post of difference is minor and favors the line of consecrations initiated by Archbishop Lefebvre.

While the consecrations of Archbishop Thuc were conferred in a secret manner, great publicity surrounded the consecrations  at Econe. but after the consecrations of Guerard des Lauriers and the Mexican priests, the attacks on Archbishop Thuc led to their losing their secret character. They became public and Rome provided these consecrations with the notoriety which they formerly lacked.

Second difference favors the line established by Archbishop Thuc.  Those consecrations performed by Archbishop Thuc were performed by someone (?) who had recognized and publicly declared the Holy See lacked a formaliter pope. Two fortunate things followed from this recognition of the absence of any Authority.  It allowed both consecrator and those consecrated to invoke the principle of epikeia in presuming an apostolic mandate and as a result rendered the consecrations conferred, not only valid, but also licit.

Bishop Carmona was the 2nd difference compared to Bishop Guerard des Lauriers.  What is understood is Bishop Carmona was correct. 

As Bp. Williamson has said, give those thirsting for knowledge, drink through a sponge initially,
lest they be overwhelmed and scandalized by it.

This is a great series of videos.  I haven't seen them in years; thanks for posting the link.

In it he brings up Malachi Martin round min. 47 or a bit later.

Can you comment on that please?  Is it true what he says there?

Yes, Malachi Martin is a nefarious character, probably a crypto-Jєω.  There have been many threads on him.

I like the part where he's talking about Martin's reaction (a bit after the segment you called out), where he stated his theory that they elected Siri on purpose, allowed him to accept, and THEN forced him out so that the subsequent plant would not have the grace of office that would prevent him from damaging the Church the way they ended up doing.

She even lays out the sequence.
1) true Pope is not known (1958)
2) Holy Sacrifice will cease and be exiled from the churches (1969)

If one were to assume this vision is now history, wouldn't other events fit the language better?
1) We will not know which is the true pope: Benedict/Francis
2) for a time, there will not be public services any more: Closing due to covid

And there are maybe a couple hundred people in the world who think Benedict is still pope.

"At first, we will not know which is the true pope."
Nobody knows what happened inside the conclave. There was no question "which" is the pope. According to the wiki the "Siri thesis" wasn't proposed until the 1980s.
And if you want to go by numbers, I'm not sure many people even know about the "Siri thesis".