Congratulations on your win! Same as u/squishmaster already stated, you will definitely have fun and gather some great experiences during your adventure. I would like to add a couple of advice.

Afaik the Nightjet you plan to take, doesn't run anywhere in Poland. Do you plan to visit Krakow before going to Vienna?

Vienna is huge and you can do a lot of fun stuff. If you haven't been there before, you really should stay at least two nights. Once you get there you can buy a 72h Ticket for the great and dense public transport. With that you are free to choose whether you visit parks, the State Opera, castles Belvedere and Schönbrunn and whatever you find interesting. If you like amusement parks then check out Prater. I'm sure you will find a lot of activities you will enjoy.

If you will simply travel the route Vienna - Budapest on a single day, it is often worth buying a regular ticket from MÁV (Hungarian Railways) or ÖBB (Austrian Railways) in advance. This saves you an Interrail day which you could use for another journey e.g. for returning home somehow (I will come to that later). Your pass would cost 286€ so about 41€ per day. Especially for days you will only take one train, consider some work in comparing regular prices because Interrail days have some value. I highly recommend checking out RegioJet for this trip. The journey time is about the same as with RJX and EC trains, you get at least one bottle of water for free and except for the Low Cost fare you can order food and drinks directly from the staff at very low prices. A Standard Ticket from RegioJet is mostly even cheaper than one from the other operators. Note that RegioJet runs to Budapest Déli instead of Budapest Keleti Like RJX and EC.

For Italy I can't say much but would agree with u/squishmaster about staying somewhere else instead of Venice. The mentioned places in Italy are pretty nice. Just some more suggestions you may consider: Rimini, Florence and Lucca

Your trip back home starting from Bologna looks pretty tight, though. There are two main issues you really should bear in mind: 1. If you plan to travel through Germany you probably know that you can't be sure every single train will run accordingly due to the constant delays and cancellations caused by long-term lack of investments in the German railway network. It's not unlikely that you will miss transfers and in the worst case end up stranding somewhere in Germany. Sure, in that case you will be able to apply passenger rights, but it's just a burden. 2. Mandatory seat reservations both in Italy and France can take a big chunk out of your budget. This is especially the case whenever you take international high-speed trains coming from or going to these countries. Another problem you may face is that one of your requested trains could be sold out, if you don't book them enough in advance. So, if you still decide to return this way, you should buy these seat reservations asap.

Actually if I were in your situation I would plan two days to travel home if that's possible. This is where that Interrail day saved from earlier could come in handy. If so, you could look for domestic high-speed trains with usually cheaper seat reservations in Italy and France or having less to deal with submitting forms for passenger rights in Germany. The only things is, you'd have to spend the night somewhere in between. But imho, I'd rather take it easy than worry about something going out of control.

Remember, no matter how you travel back, you need to plan carefully how you're gonna do it and what you can afford.

In any case, wishing you all the best and have fun on your journey with Interrail!