First, we consider the performance of the wavefunction methods. Among those we tested, DLPNO-CCSD(T) has the the smallest MAD of 1.38 kcal/mol, where the largest deviations of 2.70 kcal/mol and 3.01 kcal/mol are observed for the reactions involving the transition state (steps 3 and 4), which is consistent with other reports of overestimations of transition state barriers by DLPNO-CCSD(T). Without step 3 and step 4, the MAD of DLPNO-CCSD(T) is reduced to 0.64 kcal/mol, which is excellent in light of its significantly lower computational cost compared to canonical CCSD(T).The MADs obtained for CCSD, DLPNO-CCSD, and AFQMC are 1.73 kcal/mol, 2.61 kcal/mol, and 1.74 kcal/mol, respectively, where AFQMC has an average statistical uncertainty of ±1.10 kcal/mol. Again, the highest deviations are obtained for steps 3 and 4. As shown in Figures and, all other wavefunction methods overestimate barrier heights compared to CCSD(T), which is opposite to the behavior displayed by most density functionals. Overall, the wavefunction methods are reasonably consistent, justifying their usage as a benchmark, and the good performance of DLPNO-CCSD(T) supports its application to larger molecular systems than accessible with canonical CCSD(T).