2020 for sure. 2021 things were largely back to 100% normal in MLB in the states, except for the Jays. Anyway lots of excuses for various years. He was however the best player in baseball in 2019 (arguably) and he is still only 29, so maybe I will be surprised. We will come back to this one at year end!I don't count 2020/2021 stats it was Covid and things were messed up. The only thing I can explain in 2022 was that he was very unhappy and not focused. 2023 is what made me believe that he hadn't 'lost' it. OK maybe the stats are inflated based on metrics but 2024 regression wasn't just him - Swanson, Hoerner, Morel all were down from their 2023 stats. Also lets face it the Cubs aren't a great hitting lineup like the Yankees are. Which is why I expect Bellinger will be somewhere closer to his 2017-2019, 2023 stats. I easily see him hitting 30 bombs and 90+ RBI batting 5th in the lineup.
Regarding the Yankees lineup, is it really a good lineup top to bottom?
If he is batting in front of Judge he will get some protection stats boost, but studies have found that while its not NIL its not as significant as people expect. If he is batting behind Judge, its not a bad lineup but you are not surrounded by much better than what the Cubs had last year.
A general point more on the Yanks (rather than Bellinger), I don't see this great deep Yankees lineup. Judge is the best hitter in baseball.
Stanton? He was great in the 24 playoffs, but he has not been a good hitter since 2021.
Goldschmidt? He was really good as late as 2022, but he has been on a steady decline and is coming off a sub 100 OPS at the age of 37.
Chisholm? 99 and 107 OPS the last 2 years. Although he was very good in a small sample with the Yanks (130), so we shall see on this one. Jazz and NY might be a good fit,
Wells and Volpe are young so there might be progression.