Rise of Empire: Idle Tycoon

This is a solo, likely portrait idle tycoon game that can be played offline and is suitable for short sessions, making it highly interruptible and toilet-friendly. While generally relaxing and not demanding on hardware, progression heavily relies on watching ads or potentially paying to overcome expensive upgrades and progression walls. It's best suited for players who enjoy a low-stakes, single-player city-building experience and don't mind the monetization model.