Did the hotels have AC? Bedding good?
While you wait for replies from those who have taken the tour recently, when I was on the Adriatic tour a few years before the pandemic, the only hotel that did not have AC was the one in Plitvice Lakes National Park.
We went this past September, and all of the rooms were comfortable, temperature wise.
With the exception of Plitvice, we really didn't have any major complaints. Our room at Plitvice smelled liked sewer and the beds were questionable. The hair dryer was broken and taped back together with bandage tape:) I didn't learn until the next day that everyone else had better accommodations. So, if this happens to you, ask for a different room.
Just a bit more context to the Plitvice hotel comments which was our experience as well. That property is not representative of a RS Tour hotel. 1 night only. The rooms are mediocre. Bunches of tour buses. The meals are buffet(vast) and its serves in the many hundreds at once. All that said, its a quick walk from the hotel to one of the entrances. The strategy, and it worked well for our RS tour, was you get up early, hit breakfast as soon as it opens, walk over to the back entrance ahead of the other groups and avoid the crowds on those narrow trails for as long as possible. Its totally worth the trade off. The falls are spectacular.