Massive stars (M>8Msun) are highly influential objects, affecting both their own stellar environment and whole galaxies through their powerful luminosities, stellar winds and the generation of heavy elements. One key aspect of massive stars is their multiplicity, with binary systems of stars going through exotic evolutionary processes such as stripping events and mergers, which during giant phases leads to the generation of red novae and at the black hole stage form gravitational waves. Despite their importance and the variety of phenomena they are responsible for, the origin of massive stars is poorly understood as massive YSOs (MYSOs) are deeply embedded, distant and rare, which introduces more observational challenges. In particular, protostellar disks, which play key roles in the accretion process and formation of planetesimals for low-mass stars, are still poorly understood for massive forming stars. In this poster, I will show how fitting 3D radiative transfer models to N-band interferometric data, Q-band imaging data and spectral energy distributions simultaneously enabled us to obtain the multi-scale characteristics of massive YSOs, and in particular to probe their discs, in new detail. Inner holes and gap-like substructures are found across a sample of MYSO discs, and we tie these geometrical traits to an independently determined evolutionary sequence