Recently, Belle-II reported on the first measurement of and found that its value is about 3σ above the one predicted in the Standard Model (SM). We study this and similar exclusive processes based on by using effective field theory (EFT) in order to understand if such a deviation can be attributed to some heavy mediator beyond the SM. We point out the correlations with other observables that can be measured in the near future, in particular, and show how the similar decays to charged leptons can help constraining the allowed parameter space when working within the SMEFT approach. We also comment on the possibility of having a light mediator or a heavy neutrino species in the final state, such as a sterile neutrino which is often evoked to accommodate a few anomalies present in neutrino oscillation experiments.