If you have watched any of the interviews or behind the scenes videos, Bruce Timm is heavily involved in the creative development in these projects as is James Tucker. The directors follow their lead.
James Tucker is heavily involved in many of the most recent films because he's Executive Producer on them. Timm stepped away from being DC animation supervising producer in 2012. Since 2018, the only films he served as Executive Producer on were Superman: Red Son, Justice League vs the Fatal Five, and Gotham by Gaslight.