The optimal configuration of a Lever-assisted Tuned Mass Damper Inerter (LTMDI), comprising a lever, fulcrum, inerter, and TMD, is investigated for effectively suppressing the edgewise vibrations of the wind turbine blades, through a comparative analysis that systematically varies the positions of the inerter and fulcrum while keeping the total lever length and mass block location fixed. The equations of motion for a simplified two-degree-of-freedom blade-LTMDI system are derived using the Lagrangian approach, and closed-form expressions of the optimal tuning frequency and damping ratio for different LTMDI configurations in the blade are derived using classical fixed-point theory. Numerical simulations are performed using the NREL 5-MW horizontal-axis wind turbine blade, evaluating the dynamic amplification factor to assess the control effectiveness of various LTMDI configurations in comparison with TMD and TMDI systems. The optimal LTMDI configuration—with the fulcrum followed by the inerter, both placed to the left of the mass block—yields the lowest structural and mass block responses, effectively mitigating edgewise vibrations and enhancing wind turbine blade performance.