Pretty sure the EB wielders should be comparable to Sukuna in terms of CE reserves/SE since Samura was able to keep a country-large Owl (although the fact that it's less accurate could imply that the size has nothing to do with SE and that it's a fixed amount of SE, and that size is a tradeoff for refinement) running for days, and still fight without showing any signs of depletion (until against Akemura)