If you're going there, I'd say Frodo embodies the "suffering servant" role. As far as "priest", it's
Sam who most qualifies; remember: Frodo plays almost no role in the
Scouring of the Shire, other than trying to avoid needless deaths. Afterwards, he's basically withdrawn from activity, until his departure. It's Sam whose hard work renews
the Shire, as we return to the Low Mimetic world, though lifted by
Galadriel's gift, and Sam whose experience in the wider world makes him, in my opinion, the "priest" of what we could call
Middle-earth values in the Shire.