This article has me confused. Please explain.

If a deceased person is prayed to by a petitioner for a cure or intercession, and that happens, its declared a miracle and the deceased person is considered a saint.

https://www.livescience.com/38033-how-vatican-identifies-miracles.html

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In the Catholic religion, saints are people who are in heaven with God. Though many more people may be in heaven and technically saints, those deemed official saints of the church are ones that the Catholic church knows are in heaven. As such, people can pray to these saints, who sometimes intercede on their behalf with God.

But determining who is in heaven is a tricky proposition. That's where miracles come in. According to the church, miracles, or divine events that have no natural or scientific explanation, serve as proof that the person is in heaven and can intercede with God to change the ordinary course of events. [Proof of Jesus Christ? 7 Pieces of Evidence Debated]

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Of course we don't know if it was AI, AI rewrite, spell check, or modern journalists. But I hear after curing others he was also looking good!

Eastern Orthodoxy from the get-go used the terminology 'beatified', not canonized. When did the Romans change/correct? I dunno.

All seeing, all knowing God doesn't answer your prayers. A Saint, or wannabe saint goes to God and says, "Hey, help this kid". All knowing, infallible God changes his mind and cures the kid. Then people here on Earth, and NOT God in heaven make them a saint.

How does that all work?

And what about all the prayers and miracles to Saints that later turned out not to be real people?

Those deemed "saints" by the Catholic Church and other Christian denominations, are not regarded as deities.

Mary is worshipped as a deity despite whatever the official status is.
The religion has never been able to rationalize the status of its alleged monotheism with its claim that there are three instantiations of 'god'.
Many of the early saints are syncretic transfers from greco-roman pagan gods. They are also worshipped individually, again irrespective of the official doctrine regarding what a saint is.
As the religion spread into other cultures its syncretic nature incorporated indigenous religious ceremonies and gods into (generally) catholic festivals and saints. See for example Mexican catholicism.

All religions are defined by their official tenets..Mary is not, and never has been, defined as a deity. Like the saints, she is venerated, not worshipped, despite the ill-informed inclinations of a few. To say otherwise is like denying the Ten Commandments as essential to
Judaism because some of of its adherents choose not to follow them.

The explanation of the Trinity is rational in its analogy to substances like water. They are one substance, even though their physical forms differ, and are assigned unique names.