Planet radius as a function of orbital period for known exoplanets from NASA Exoplanet Archive with a radius precision below 8%. We highlighted the Neptunian desert, ridge, and savanna regions from Castro-González et al. (2024). The colorcode represents the observed density of planets. TOI-756 b is depicted as a dark red hexagon. Light blue symbols represent sub-Neptunes in systems hosting eccentric giant companions: crosses indicate systems with only giant planets, while circles correspond to systems containing both small and giant planets. In contrast, dark blue circles represent sub-Neptunes in systems with non-eccentric giant planets. The description of the selection is made in Sect. 6.3.1. This plot has been generated with nep-des (https://github.com/castro-gzlz/nep-des/).