Scale separation between the external spacetime and the internal compact manifold is a fundamental requirement of any consistent string compactification. In this talk, I will discuss the possibility to realise such a paradigm in the case of 3D reductions of the Type II string on twisted tori including fluxes and a single type of orientifold planes, giving rise to a specific class of 3D gauged supergravities known as RSTU models. Making use of the embedding tensor formalism, we construct the RSTU flux model associated to all possible T-duality frames and systematically chart the landscape of vacua. This results in 56 inequivalent families of AdS_3 and Mkw_3 vacua, which are all perturbative stable and exhibit different amount of supersymmetries. Only two AdS_3 vacua, appearing in the Type IIB+O5 duality frame, present full moduli stabilisation and scale separation. All other vacua do not stabilise all the moduli and fail to realise scale separation even assuming an additional stabilisation mechanism.