You asked
Is the leica m10 monochrom hard to focus?
Here is what the site says about that.
From Leica M10 Monochrom: Leica M10 Monochrom: A rangefinder by Leica with a 40.9-megapixel full frame sensor, announced in 2020. Black and white only, on a 40-megapixel sensor. Specs - Maker: Leica - Mount: Leica M - Sensor: Full frame, 36 x 24mm, crop factor 1.0 - Resolution: 40.9 megapixels - Stabilisation: none in the body; use stabilised lenses for slow shutter speeds - Announced: 2020 - Type: rangefinder Focal lengths on it Full frame is the ...
From Buying used: Checking a camera body: - Shutter count. Shutters wear out eventually. Ask for the count, or read it from a test photo's metadata with an online tool where the brand supports it, and compare with the rated life for that model. - The sensor. Take a photo of a plain sky at f/16 and look for dark spots (dust is fixable; scratches are not). - Ports, buttons and dials. Try every button, the card ...
Quoted from this site's pages.