Enrichment of possible undiscovered planets in the inner disc by the impacts of planetesimals that formed in the outer disc for all four simulation scenarios (with blue we denote the HDM-HPM scenario, with green the HDM-LPM one, with orange the LDM-HPM one and with yellow the LDM-LPM one). Top row: normalised mass fraction of accreted material onto lunar-like, Earth-like and super-Earth targets, with the horizontal dashed line marking the water mass fraction on Earth (5×10⁻⁴, Morbidelli et al. 2000) shown from left to right. Bottom row: atmospheric enrichment of mini-Neptune, Neptune-like an Jupiter-like targets assuming a solar-like metallicity atmosphere, with the horizontal dashed line marking Jupiter’s 3× solar atmospheric metallicity (Atreya et al. 2018), shown from left to right.