So, doing sankhāra for any sankhata inevitably leads to suffering.
In case of liked sankhata it leads to suffering via seperation from it. In case of unliked sankhata, it leads to suffering via meeting them.
We have upādāna for sankhata because we avoid their tilakkhana nature.
While doing sankhāra for any sankhata thinking that it will lead to sukkhā (under ignorance of their true nature), it paradoxically only leads to more and more suffering. While having possibilities of being born in any realm doing various sankhāra (having majority of births in apaya).
So this all efforts to earn much sukkhā from sankhata is all unfruitful and futile, leading only to suffering at the end of the day, never to any permanent happiness and niccā state. So there are of no essence. Anattā.