Animator State & Animator SubStateMachine uses IMGUI to render. Even if you enabled SaintsEditor, the StateMachineBehaviour will display incorrectly for some SaintsField attribute (because IMGUI still have some problem in rendering).

Please read SaintsFieldAnimatorEditorHijack to hijack Unity's default drawer to UI Toolkit's implement.

Warning

This feature uses a lot of undocumented/internal API from Unity which may not work at all in feature version of Unity.

Before:

After: