Similar to Fig. 1, but instead displaying data from the four CHEOPS visits described in Sect. 4.1.2. Top panel: 11 d observation. Transits of planets c and d at ~ 2459075 BJD occur too close to each other for their corresponding lines to be individually visible in the figure. Bottom-left panel: subsequent observation scheduled to confirm the presence of a planet with a 20.7 d period (planet g), which overlaps with a transit of planet e. Bottom-right panel: final observation scheduled to confirm the presence of a planet fitting in the Laplace resonance (planet f, with a period of ~ 15.23 d), which overlaps with a transit of planet b.