A friend has a villa in Sarnarno, about an hour west of Ancona. When we go for some impromptu restoration, we often go via Belgium, Germany A4/A3/A7, Austria and straight across the Brennero to Italy. You can use motorway almost all the way or include bits of interest like the Fernpass and old Brennero road down to Trento.
We normally have a pause at Frankfurt. But it is slightly off the direct route.
You could use the A61, turning right at Kerpen. Most of the A61 is two lane and the Hgv overtaking Verboten sections are unfortunately rather too infrequent, but it is an attractive run.
Near Mannheim the option of staying on the A61 to Hockenheim, the A6 to Heilbronn which would include passing - or not - Speyer and Sinnsheim and on to the A7 at Kreuz Feuchwangen.
The alternative is to go down to Karlsruhe then Stuttgart and collect the A8, which would take you to the A7, down to Austria.
As Switzerland is a signitory of the Schengen Agreement, there are lots of unattended border crossings - but probably not where an Autobahn is involved. One of my normal bimble routes is from Pontarlier through the corner of Swiss Jura to Winkle, to squeeze between the Aeroport and Basle, cross the Rhine and take the A5 north.
No checking - or even people - for the last few years.