Prior to version 1.21.5, wolves would spawn relatively commonly in the wooded badlands biome in large packs which could reliably be found in the dirt-covered portion of the biome. In the latest snapshot (and some before it), they are incredibly rare and seldom generate in packs of more than 2 or 3.
Steps to reproduce
Create a world in version 1.21.4 and head to the nearest wooded badlands biome containing dirt/blocks wolves can spawn on (I've used the seed 681661981736366465 with wolves spawning near the coordinates X:668 Y:128 Z:-1336). Note that a wolf pack spawns here with others throughout the biome. Re-create the world in 1.21.5 or a later snapshot, head to the same coordinates and see there is no longer a wolf pack spawning.
The Environment field is supposed to only contain PC details.