In the United States we had many problems when highway=trunk was used in the past to indicate enhanced construction that wasn’t quite up to motorway standards. Doing so meant that data consumers had no way to know which were the important long-distance routes that need to be shown on national level maps, but which aren’t motorways. This resulted in low-zoom maps having patches of trunk roads around cities where there was enhanced construction, but resulted in big gaps in the transportation network when important roads go through sparsely populated rural regions and become 2-lane highways.
For the past few years the US community now uses highway=trunk to indicate the most important roads in the highway network that aren’t up to motorway standards, regardless of their construction level and whether or not they use interchanges or at-grade crossings:
https://wiki.openstreetmap.org/wiki/United_States/2021_Highway_Classification_Guidance
We now use expressway=yes to designate those roads that are of enhanced construction (for example with acceleration/deceleration ramps). Key:expressway - OpenStreetMap Wiki
By using a separate key for this enhanced construction the highway=trunk|primary|secondary|tertiary tag can be used to indicate the connectivity importance of the road. For example, an enhanced-construction road may only server a locally-important destination, so it is completely valid to tag it as highway=secondary+expressway=yes.
Maybe the Italian situation is too different, but I encourage thinking about connectivity classification (highway=*) as a separate orthogonal concept from the level of construction (expressway=yes) or access restrictions (motorroad=yes).