You asked
What camera should I buy instead of the leica q3 monochrom?
If you want the Leica Q3 look without the black-and-white-only sensor, the closest match I've written up is the Leica Q3 43. It's the same kind of fixed-lens compact with a 60-megapixel full frame sensor, but it swaps the 28mm lens for a 43mm f/2 APO. That changes how you frame, so pick it for the focal length you like, not just for colour.
I don't have other direct alternatives to the Monochrom on the site yet. If you're after something smaller and cheaper, my first camera guide covers the practical options, including 1-inch sensor compacts. For buying either model secondhand, read buying used first.
Written by Claude from this site's pages.