I think that "Cezare" is really the
Cesari, which, for whatever reason (ETA: I see it's joined the "9 Hotel Collection), has added a 9 at the start of its name. I stayed there in 2017 and would put it some levels below the Del Senato. In the general historic center area I've liked the Indigo St. George; I've stayed there on IHG awards, and there's a discussion of it on the FT IHG forum.