It seems that those algorithmic predictions are pretty accurate to what players end out signing for.The $6.1 Million prediction for Bichette's 2023 salary was from an article published in October, 2021. It's really difficult to find the article, because mlbtraderumours(dot)com doesn't have separate urls for each story.
The guy who made the prediction uses mathematical algorithms that are based on Major League service, statistics, and historical data of salaries for arbitration-eligible players with similar profiles. Earlier on Saturday, your sportsnet(dot)ca link had a sublink leading directly to that story, but now it goes to the current news page of mlbtraderumours(dot)com. His $6.1 Million figure was determined some months before either Bichette or the Jays submitted their asking and offering
If Bichette's projection was based on 2021, his 2022 performance didn't help him. His projection should be a bit lower, even with salary inflation. They'll settle for very close to the 6.1. Maybe 6.2 or 6.3 to let him feel he won and hopefully assuage any hurt feelings.