Does anyone know what these little green collars are or where they go?

I just put new ball joints in without these thinking they were just like thread
protectors for shipping or something. But now that it's all back together and my steering doesn't return to center, I'm thinking my dumba** needed to put those on, but it doesn't make sense to me where they should go

I think it's more likely the cone washers they sent weren't the same angle as the factory ones. I have no clue what those green things are for. Are they inserts that are supposed to be installed in the cone washers they sent you with their kit?

Not that I can tell, the cone washers were just solid metal with no cutouts for inserts or anything. I didn't really look to see if they were correctly angled, just assumed they fit.

They definitely make differently angled cone washers, you should be able to just visually see if it's seated or not without taking it apart.

Jack up the front of the vehicle and make sure the steering is nice and smooth from lock to lock (engine off), you probably just need to get an alignment.