I am not sure I explained correctly. The ARC is not used when I am using the fireTV stick as the FireTV stick is connected to the AVR and not the TV.
Anyways, I am going to get the 4K firetv stick. I hope I can get it for free as I work in the same company

People who are going to buy this TV, please consider the cost of the FireTV stick as well.
The Samsung Frame is not a bad option with 20K approx more, with better motion handling, gaming and probably better support.
I didn't want to buy Samsung anyways as I am not very happy with their previous TVs I have bought - neither support nor the reliability.