Expedition cruises in these regions will be more "Expedition Lite" but still an enjoyable experience. If your itinerary includes Iceland things may get a little more adventurous but still nothing too crazy. We've done15 Silversea cruises in total, about half expeditions, half classic cruises. We tend to prefer the smaller out of the way ports, and the more wild landscapes, that we visit with expedition cruises.
We have not done a dedicated BI itinerary but have visited Finland and Sweden just this past June on Silver Wind, so the latitude may be similar. I did a trip report here on CC which should give you a sampling of a typical expedition cruise in another region of Northern Europe.
It would be helpful if you listed your exact voyage and itinerary, so we could give you more detailed information about the stops and what you might see. I looked at the 2025 Silver Wind itineraries and they run the gamut, so your experience will vary depending on which one you booked. I can't tell whether you're on one of the itineraries which include Iceland or not, which might significantly alter your experience.