Definitely AR/VR. I’ve been following it since 2013 and working in the field since 2018. I suspect many big Android phone OEMs will get into the space in the next year or so and it will explode in popularity.
My guess is that Google will ship a commodity AR/VR operating system, which will be used by other phone manufacturers like Samsung, Asus, etc. to power their headsets, just like Android on phones.