Thanks Scott and both Peters.
As for the RX10, I first got an RX10 (original) for a trip to France a couple of years ago, not wanting to be bothered with a tripod and the bunch of lenses I had for my Canon 5DII. My local camera store suggested the RX10 and let me try it for a day, and I was enthralled. With my Canon, I never used a lens beyond 105mm, so having a sharp Zeiss lens that was sharp from 24mm to 200mm (FF equivalent) was a treat, and finding that shots at 200 were easily hand-holdable was the frosting on the cake. I soon sold off all my Canon equipment.
Then last year I upgraded to the RX10III, which goes to 600mm (FF equiv.), still easily hand-holdable and sharp. That has opened up a whole new world of more distant shots that I never even considered before.
The camera is much lighter than my Canons, largely because of the digital display, which is much better than I had expected (but still not the same as a good optical view finder). And the Sony menu system is often confusing, but those are small tradeoffs, IMHO.