My friend just did a Rick Steves tour (Italy) and raved about it.
Be sure to read the description of the Rick Steves tours carefully. Years ago, I used his travel books extensively when I went to England.

I would have loved to do one of his tours someday, as they seem to make sure there is a healthy mix of doing things with the group and also having some alone time, just exploring the destinations on one's own with some experienced advice and input from the guides if one wants.

I was looking at his tours of Paris & other parts of France, right before the pandemic. I'd be spending most of my free time in the Louvre and the Impressionists Museum.
But now his tours are no longer appropriate for me. They require one to be quite fit and healthy. I have a chronic illness that can leave me short of energy at times. Even though I walk practically everywhere here in NYC, doing a few miles hike here and there, up and down hilly mountainsides,
every day, may be too much for me now. (Although, that's when I'd opt out for some alone down time.)
And I have a bad back. Some places they stay at, while wonderfully quaint and mom & pop owned, are smaller or sometimes older and do not have elevators. One's room might be on the 4th floor of a walk up and you'd have to carry all your luggage up by yourself. That alone is a deal breaker for me now.
And no way should the type of people below even think of doing a Rick Steves tour, let alone an average one. (There are tours for just seniors which I hope may be gentler and more accommodating for people with health issues.)
but some have had people who had no business taking a tour that required walking/standing/getting on or off busses. Very frustrating. I feel like I missed most of the Vatican tour because one couple had to sit and rest every block and we ran out of time.