Baptisms are presumed valid unless there is actual evidence that the wrong words were used.
Evidence would be something like the baptism rite of certain Protestant churches often or usually uses the wrong words, or someone has a video recording of a baptism where the priest or deacon is using the wrong words. In the cases where a Catholic clergyman has been found to have used the wrong words, the dioceses try to reach out to everyone who was baptized by him out of an abundance of caution.
Yes, it’s a bit of a frustrating situation, especially since (as discussed on the other threads) there was a common belief among many otherwise very orthodox Catholic clergy that the use of the word “We” might be okay, even though orthodox Catholic clergy would caution that it is always better to use the EXACT words prescribed by the Church so as to avoid all doubt. But in the absence of evidence, we presume validity and trust in the Lord to provide whatever might be missing through no fault of our own.