You cannot play all animations groups at once; you may play one animation group with all animations in it.
scene.animationGroups.forEach((g)=>{
g.stop()
})
let someAnim = scene.animationGroups[2]
someAnim.play()
someAnim.loopAnimation = true
As I already wrote, animations in your model are badly done and actually are broken. This relates to the model, not to Babylon. Please read more documentation