"Barchetta Excelsior" - that sounds like the name of an hotel. Which town or village is that in?
As Laura says, Como is a big lake, depending on which town or village you are staying in the options to get to Zürich are different.
I WOULD NOT go to Zürich by bus, that will be slow and uncomfortable. A train will be a lot more comfortable. And, there are very limited long distance international bus services to Switzerland, train is the normal method of Public Transport.
Swiss Rail or should we try Gotthard Panorama
"Gotthard Panorama" is not a railway company, it is a named tourist train operated by SBB (Swiss Federal Railways) in additional to their normal service.
Once you have decided where you are staying on Lake Como, and where the nearest station is, you can look up trains from there to Zürich on the SBB website: https://www.sbb.ch/en
Or you can look at this rail map of Switzerland: https://www.sbb.ch/content/dam/infrastruktur/trafimage/karten/karte-sts-pass-gueltigkeit.pdf
All Swiss rail routes (shown in red on the map) have at least one train per hour.. On the bottom right of the map you can see lake Como (like an upside-down Y). The rail lines in Italy are shown in grey.
Finally, why are you going to Zürich? It is not normally a place tourists go on their first visit to Switzerland, it is not in the mountains. Unless you are actually heading for Zürich airport, and not the city.