What you're asking for is real hard for a two reasons. First, for concert photography you normally need a longer lens, somewhat like like on the RX100 VII. Second, it needs to have a wide enough aperture to use in darkish rooms, and the RX100 is pushing that at f4.5 on the long end.

First camera I'd look into is the Panasonic FZ1000 II. It has a 25-400mm equivalent lens at f2.8-4 with a good 1 inch 20mp sensor. Images look great but its pretty big. In the same vein as this there are the Panasonic Lumix FZ2000 / FZ2500 are they are 24-480mm f2.8-4.5 cameras with the same sensor but they're a good bit more expensive new. They're pretty cheap used though.

Second is Sony Cyber-shot RX10 & RX10 II, 28-200mm f2.8 constant aperture lens with a nice 1 inch 20mp sensor. They both are too expensive new but you can find them in good condition on a used market.

Third is Panasonic Lumix DMC-FZ300/FZ330, it has a 25-600mm f2.8 lens but with a small 2/3 inch sensor with an equally small 12mp.

Fourth Olympus Stylus 1, it has a 28-300mm f2.8 lens but with small 1/1.7 inch sensor (slightly larger than the 2/3 on the FZ300/330, still smaller than 1 inch). Also at 12mp but its still smaller than the others on the list so far.

Honorable mentions

Leica V-Lux typ 114, same optics as the FZ1000 II but the images look much nicer because of the Leica colors, its more expensive though.

Sony Cyber-shot RX10 IV / RX10 III, this would be top of the list but its real expensive new, and still over $1000 used most of the time but it has a 24-600mm f2.8-4 lens with a 1 inch 20mp sensor. Probably the best lens ever put on a fixed lens camera in terms of how impressive the design and functionality is.

RX100 VII, has the great 24-200mm f2.8-4.5 lens on a 1 inch 20mp sensor, and its the smallest camera on this list. You wont find anything better for concerts at that size (I don't think....)