I only have HDMI ARC on my tv but I use an Xbox one X which suppors Atmos. So I have my Soundbar connected to my Xbox and have no issues playing Atmos content even though my TV only has HDMI ARC.
As long as the receiver, in my case the xbox one X, could be a Bluray player or PlayStation supports Atmos, it doesn't matter if the TV is Atmos capable or not.