TR App with hotel bike (aka Peloton)

I am new to TR and been looking for a workaround as I do not have a power meter but do have access to a few Peloton bikes at work and a Peloton account linked to Strava which is linked to TR. Could you explain why the need for a head unit? Could I do the TR workouts from my cellphone and follow along in Peloton’s Just Ride? Any insight is much appreciated.