Theoretical interpretations of particle physics data, such as the determination of the Wilson coefficients of the Standard Model Effective Field Theory (SMEFT), often involve the inference of multiple parameters from a global dataset. Optimising such interpretations requires the identification of observables that exhibit the highest possible sensitivity to the underlying theory parameters. In this talk, I will present results based on our recently developed open source framework, ML4EFT, that enables the integration of unbinned multivariate observables into global SMEFT fits. In particular, I will focus on optimal observables in top-quark pair and Higgs+Z production at the LHC, demonstrate their impact on the SMEFT parameter space as compared to binned measurements, and present the improved constraints associated to multivariate inputs. Since the number of neural networks to be trained scales quadratically with the number of parameters and can be fully parallelised, the ML4EFT framework is well-suited to construct unbinned multivariate observables which depend on up to tens of EFT coefficients, as required in global fits.