Both were originally steam.
Zanardelli was built by Escher Wyss in 1903, and was in service until 1976. She emerged again in 1983 with diesel-electric propulsion
Italia was built in 1909 by Odero at Sestri Ponente and was steam until 1975, entering service agai in 1977 with diesel-electric propulsion.
One of them, and I forget which, has a large drawing of a horse-powered paddle steamer in the upper deck amidships space.
Their ssilings can be a bit difficult to track down, but
www.swissitalianpaddlesteamers.com has details of which sailings they have been on for the past few years,, from reports by enthusiasts.
There were also a number of paddle steamrs on the lake which were converted to screw motor vessels, indistinguishable from purpose-built motor vessels.