That’s one of my gripes about the Vatican II reforms to the liturgy, you now have options, options, options. Go from one Catholic parish to the next and the liturgy is never the same.
One of the strengths of the Catholic Church in the old days was our universality. You’d go to any Catholic Church and the Tridentine liturgy was the same!
Go to any Traditional Latin Mass parish and all their liturgies are the same.
In my opinion the Church really needs to settle on a universal form of liturgy. We need to return to universalism. Without it you have splinters and fractures within the Church, and we’re seeing this clearly today where the liturgy is endlessly debated, “how is the Ordinary Form best celebrated?” Not to mention you have camps of Catholics who are either traditionalist, or “novus ordo” as they say.
As for SSPX, I don’t trust them. I find them highly suspicious. The Vatican has been quite accommodating to traditionalist groups within the Church. When FSSP broke away from SSPX, FSSP was elevated to Pontifical Right status within three months! Many orders take 20, 30, or 40 years to achieve that. There is also ICKSP. Rome clearly cares about those who prefer the Tridentine Rite, and they’ve extended the olive branch many times to SSPX, but SSPX keeps finding excuses not to come back into full communion with Rome. I think at this point they have made being disobedient a central part of their identity, they won’t know what to go do with themselves if they come back into full communion. I feel like all their meetings with the Vatican are just a dog and pony show at this point.