I were you, any route that is served by italo I would not use Trenitalia.
italo is the private railroad company in Italy. It has forced Trenitalia to improve service, but still not good enough than italo. italo now has a fairly large network that other than regional trains, there is no need to use Trenitalia on popular routes.
Their trains are newer, seats are more comfortable, website is easier to use. If you travel as at least 2 persons together, the "group" tickets are cheaper than Trenitalia.
Personally I would also check the F class in "group" ticket pricing - often when buy early the price per person is only a few euro extra than a regular single ticket in 2nd class. It also offers a very cheap, a few euro cost "insurance" that allows free cancellation up to 72 hours before travel last time I bought tickets.
https://www.italotreno.it/en
