First time Europe trip Itinerary (early draft)

Making my first trip overseas. I’m an experienced road tripper on the lower 48 but this will be a new experience. I have done some research but wanted the perspective of real people who have been there before

Heading out in Early September. Fly into Milan. Planning on spending 3 days in Northern Italy. After that head up to the Jungfrau area of Switzerland to spend 3 days there. Then off to Germany for a couple days. Be visiting my Aunt and Uncle near Ansbach for a couple days. Thinking about stopping at the castle of Mad King Ludwig on the way up. After that head down to Austria to spend a day. Then it will be off to Slovenia to spend 4 full days. Then end the trip with a trip to Plitvance Lakes National Park before flying home out of Zagreb. Thoughts?

I am having trouble narrowing down Italy. Sounds like the Dolomites will be difficult to fit in with going to Switzerland after. For my interests of Nature, history, and local culture Verona sounds like a must. Then either Lake Como or Venice. I have heard mixed reports on Venice. Some say it has one of the best preserved history you can find. Others says it’s overrated, overcrowded, and the canals stink.

I’m also unsure what to do in Austria. Any suggestions to compliment the other stops?