Two years ago, we went to southern Italy for a month. That trip included the then 11-day Rick Steves Tour of Sicily. (Now it’s up to 12).
I think the responses so far have focused more on the “buddy system” than I would to address your questions about free-time opportunities.
If our one RS Sicily tour is a good example of the RS approach, I’d say that RS tours are pretty fast-paced in terms of multiple opportunities to see special sights, with good local specialty guides who add perspectives and local information that you may not easily get by traveling independently. And we never had to stand in line to get tickets.
As for free time, we had half of our dinners on our own and perhaps bit more than half of our lunches on our own. The one meal regularly provided was breakfast, but you probably don’t want beer with breakfast, anyway.
We often had a few hours during the day on our own. And you could certainly let your buddy and your main guide know that you won’t be with them for whatever group activity you plan to miss.
At times, you may choose to have one of those meals on-your-own or free-time eves or afternoons with another person or group on the tour. Like, hey does anyone want to join me/us for whatever tonight. Or not.
As for the “buddy system,” the buddy is not your travel partner. It is someone new you pair up with on the first day so the Guide can make sure no individual or no couple gets left behind, without running a risk of miscounting 24 people who are milling around. My wife and I each had separate buddies. Whether you and your “buddy” get close is up to each of you. Seems to be a good system that works well.
At the end our 30-day trip, we posted a Trip Report that compared our “three ways to travel” - the RS Tour, a “self-guided” bike tour, and more traditional travel on our own. That report might be useful to you. See, https://community.ricksteves.com/travel-forum/trip-reports/southern-italy-30-days-three-ways-to-travel
The only other thing I would add is that you should look at particular itineraries with an eye to how much bus time is involved on each travel day and how that bus time may be broken up by a sight or activity along the way.