daf: Yes, but we Pasken in Shulchan Aruch (and there is Kim’at no disagreement in any of the Achronim) that there is a Mitzvah to eat on Erev Yom Kippur. So while the Rambam’s Shittah might be interesting, it’s not relevant L’ma’asheh.
(Pashut P’shat, by the way, is that the Rambam Paskens Tosefes Yom Kippur is D’oraisa from the Passuk of Mei’ever Ad Erev, so now there’s no Drashah left for eating on T’shi’i. It’s a Pele on the Mishnah B’rurah that he uses that same Passuk for both Dinim and seems to say both are D’oraisah.)