I’m an outsider looking in at this point, but I think this would essentially turn the SSPX into another FSSP.
Yes, but they're already halfway there as it is.
As I mentioned in the context of the controversy over "Pope" Leo, the SSPX paradigm regarding the crisis has already aligned with that of FSSP.
There are two basic paradigms:
1) V2 represents a substantial rupture, and there's no "fixing" this crisis in the Church until it's rolled back, declared null, and sent packing along with the New Mass and all the post-V2 "papal" Magisterium.
2) Since V2, due to various bad actors mostly at lower levels, the Church has gotten too liberal and there are many Modernists in the hierarchy now, and while "95% Catholic" (per +Fellay ... the same line that Schneider takes), a few course corrections by the right conservative "pope" would change the trajectory of the Church back on the right course.
It's precisely because of this shift from #1 to #2 in SSPX that the Resistance parted ways and labeled SSPX the "neo-SSPX".
In the one paradigm there's no difference in kind between Catholic Church and Conciliar Church, but a difference in degrees, as in degrees of liberalism vs. degrees of conservatism.