Simulated S/N grids showing the expected constraints that can be obtained by obtaining more data. The dotted white lines represent the contours of the simulated data, with S/N=3 (dotted) and S/N=4 (solid) respectively. The dark blue lines represent the contours of the injection recovery tests of our real eight transit data set shown in Fig 5. The constraints are shown for 16 CRIRES⁺ transits, that is, another eight transits with CRIRES⁺ added to the eight nights presented in this manuscript (left panel), for one transit and six transits observed with a fictitious K-band spectrograph at the ESO-ELT (middle panel and right panel, respectively.