It should not be that surprising that a player coming off a 4.6 WAR season, with that talent level supported by prior MLB data, with 4 years of control remaining, would be worth slightly more than a 60 FV prospect.
Again, Moreno was only the "#1 prospect in baseball" because of proximity and circumstance. By talent he has always kind of been functionally equivalent to 10-15 other prospects. Look at the Fangraphs prospect board for the 2022 update it has Gunnar and Eury Perez as 65 FV and than Moreno #3 at 60 FV but 13 other dudes with the same FV.
One other 60 FV guy on that list has been traded - Noelvi Marte. He was traded with three other good prospects for just 1.5 years of Luis Castillo, who was coming off a 3.8 WAR season and in the midst of a 3.7 WAR season.
That should make a Jays fan feel better about trading a 60 FV prospect for 4 seasons of a guy like Varsho.