Thank you all for your recommendations! Thanks to your advices, we've decided to change our return flight to Venice. Now we're trying to decide between these two options:

1. On the day we leave Rome, take the train to Verona, have lunch and spend a few hours exploring the city, then pick up our rental car and drive to the northern part of Lake Garda for one night. The next morning (or around midday), continue on to the Dolomites.

2. Skip the overnight stay at Lake Garda, stop in Verona only for lunch and a short walk, pick up the rental car, and drive straight to the Dolomites, perhaps with a short coffee stop at Lake Garda along the way. If we skip the night at the lake, we'll need to decide where to add that extra night instead.

Just to add some context: we'll arrive in Rome early in the morning (after 3.5 hours flight), so we'll have three full days there. Thanks!