Most stars form in multiple systems and clusters, especially OB type stars are frequently found in a clustered environment. Yet, the early phase of star and cluster formation is still poorly understood, and little attention has been paid to the complex interplay between the physical processes and the chemical evolution of the gas. The enrichment of the star forming gas in complex organic molecules (COMs) is associated with deeply embedded heating sources, referred to as hot cores. The ALMA-IMF Large program images 15 of the most prominent Galactic protoclusters over various evolutionary stages. Beyond the rich core population uncovered by ALMA-IMF, we identified a sample of ~70 hot core candidates using CH3OCHO lines. Our main result shows that the most massive cores are all associated with CH3OCHO emission, suggesting that all massive cores undergo the hot core phase. The hot core candidates exhibit emission in a variety of COMs highlighting their molecular richness. We use a statistical approach to constrain the physical conditions and the diversity of COMs towards this sample of hot cores based on the non-continuous ~6.7 GHz wide frequency range of ALMA-IMF. We put in context our results with our understanding of the global molecular diversity of hot cores and hot corino like objects.