EU travel suggestions between 12/26 and 1/15 [closed]

I'm planning an EU trip with my family and would love to hear thoughts or suggestions on where to go, with a few things in mind that I'll explain below. It'll be my wife and I, my 5 kids ages 3 months to 9 years, and my parents (so 4 adults 5 kids).

We arrive in Amsterdam Nov 15 and stay for a few days, then train to Hamburg -> train to Copenhagen -> overnight ferry to Oslo -> train to Stockholm -> overnight ferry to Helsinki -> fly to Prague for Christmas (Dec 19 - 26). We stay in each place between 4 and 7 days.

We're trying to figure out where to go after Prague. Constraints are:

1. Trying to keep costs reasonable (under $200/night if possible)
2. Avoiding Italy and Zurich as we've already been there. Staying in Airbnbs the entire time (so far).
3. Travel times of ~6 hours or less preferred
4. We'd like to make it to Brussels by 1/8 or so to check it out before we fly out of Amsterdam on 1/15

Places we've considered so far:

1. Vienna - prices are quite high near 12/31 though
2. Salzburg - prices are extremely high ($450+ per night) - probably not an option
3. Budapest - somewhat expensive for this time of year, and puts us further away from Brussels

Maybe we need to head more West?

1. Munich is a 6.5 hr train ride away
2. But Munich to Paris is 9-10 hours

Would like to see at least some part of France, if not Paris, before heading up to Brussels.

Complicated question but would love any thoughts. We're quite open-minded within the constraints I mentioned.