Where to visit for a few days in May?

Hi! Me and a friend are planning our interrail for this May, and for now there's a gap in our itinerary. We plan on going to Slovenia during week 19 of this year (that's 4.-10.5., but we will probably not stay for the whole week), and after that our next stop is in Northern Switzerland where we should arrive on the 14th of May. We can't go there much earlier because we are visiting friends and we've agreed to visit for that weekend.

That leaves roughly a 3-5 day gap in our itinerary. Any suggestions? We're open to pretty much any type of place since we already have a good mix of places (capitals, seaside, lakes, mountains etc), the only criteria is that it should be fairly affordable (definitely not over 100e per day per person). We had planned on going to Austria then, but we don't want to go to Vienna because the gap is during Eurovision week and we haven't had any luck finding cheap accommodation elsewhere in Austria.

We're open to all suggestions 🫶🏻 thank you in advance