No, YouTube does not support Dolby Atmos. Google on the other hand is working to develop and launch its own-brand equivalent to Dolby Vision HDR and Dolby Atmos.
Dolby Atmos
Yes, Netflix support Dolby Atmos. But, you need a premium Netflix subscription, a TV or device that enables Dolby Atmos, a soundbar, or a speaker setup enabled with Dolby Atmos.
The Dolby Atmos audio format features a 3D sound system, using ceiling speakers to reproduce sounds. Does Spotify support Dolby Atmos technology?