Entangling distant spins via a shared magnonic bus typically faces a tradeoff: stronger spin-magnon coupling increases the entanglement fidelity, but also the spin decay rate. We propose a protocol that breaks this tradeoff. The magnons couple only to a transition outside the computational basis, in which the Bell state is created. Our protocol is probabilistic, and weak coupling mainly reduces the success probability, with only a small effect on the fidelity. We analyze a setup where the spins are two nitrogen-vacancy (NV) centers near a magnetic wire. In the absence of NV dephasing, the protocol reaches unit fidelity with a maximally entangled state, for arbitrarily weak coupling. In our simulations via the Monte-Carlo wavefunction approach, the NV-magnon coupling is taken to be one-third of the magnon linewidth. Considering finite NV dephasing, we predict a fidelity of $>0.99$ for a state-of-the-art rate, and an optimal fidelity of $0.91$ for a moderate rate, both at $0.6\%$ success probability.