Kyle Tucker - 142 wRC+
Cody Bellinger - 121 wRC+
Kyle Tucker - 4.3 fWAR
Cody Bellinger - 3.2 fWAR
Kyle Tucker has been 20% better offensively and been worth a full win more. The only reason it is this close is because Kyle Tucker has gone cold for a bit. In all of his full seasons, Kyle Tucker averages a 142 wRC+. which is what he's done this year. Cody Bellinger hasn't had a 142 wRC+ season since 2019, and he did it one time. Since his resurgence he has had a 122 wRC+, so these are pretty standard numbers.
It should also be noted that Kyle Tucker has had bad batted ball luck. Bellinger has outhit his xData. This means moving forward we should expect Tucker to be better than he's been and Bellinger to be worse.
Kyle Tucker wOBA vs xwOBA - .370 vs .390
Cody Bellinger wOBA vs xwOBA - .348 vs ,331
If Tucker had a .390 wOBA like his xwOBA suggests, he would be the 7th best hitter in baseball tied with Cal Raleigh. As is he is tied for 14th. Cody Bellinger is 48th, however if he had his xwOBA, he would be the 78th best hitter in baseball.
Pay. Kyle. Tucker. It is not close between Cody Bellinger and Kyle Tucker. One of these players is an elite baseball player who has had bad variance and the other is a fine baseball player who has had good variance.