Update: Threads 1.1 is out today and adds what you asked for. Both screens now read your project’s resolution, portrait included, and the text scales with the screen, so a 1080 x 1920 layout stays readable. Tap a node to select it and tap it again to jump back there. The whole chart fits on one screen, so there is nothing to drag or pinch zoom. We tested it at 1080 x 1920 in both RPG Maker MZ and MV. It is a free update, and the devlog on this page has the details.