I'm certainly no expert, but I know what I saw last year: JDM was a sucker for low and away sliders.
In 2018, about which I raved in my earlier post, JDM's OPS was 1.031 his WAR was 6.7, and he batted in 130 runs. Last year his OPS was .790, his WAR was 1.1, and he batted in 62 runs. You seem to think last year, for which JDM was paid $20M, was just fine and dandy.
This year his OPS is back up to .951 and his WAR is 1.0 for 1/3 of a season. So, as I also pointed out, maybe he or his hitting coach fixed that tendency to chase low and away sliders.