One thing we know for sure is that Gallo is by far the healthiest, his issues have been of the 'forgot how to hit baseballs' variety. He had just a 0.2 bWAR last year in 350 ABs despite very good defense as always, plus 19 HRs and a ton of walks as Blizzard said, but his teams (NYY then LAD) were still somehow an almost impossible 74-29 when he started, that's a 116-46 pace.
Oh, and he had 163 Ks in 350 ABs (!!!!). LAD did not give him a single AB in their 4 game NLDS loss to SD, Bellinger started the first two games and went 1-6 (a single) with 4 Ks.