From Roon 1.8 is live!:
This complete overhaul of the Roon interface addresses a number of long term feature requests we’ve heard from the community, including vertical scrolling, portrait orientation on tablets, and a phone interface that now includes near-complete parity with Roon’s desktop apps.
The “Now Playing” screen is obviously very different from the one on tablets and desktops. Maybe you should write a feature request in the appropriate section of the forum for that feature on phones?