OEBB Nightjet

Hallelujah, thankfully the Austrian railway exists, which is currently giving the DB a considerable helping hand.
Night trains are back, and car trains are also running again, with more to come soon, which is why this link exists. At the moment, you need to get off in Innsbruck, where you can rent a car or continue your journey by train to Bolzano.
There are good connections:https://www.nightjet.com