I had two mouses get that problem about a year in. One was the MX Master 3S, a 100 € mouse. For that price point, it's entirely unacceptable for the mouse to only last a year. Good thing it had a two year warranty, but it's such a hassle to be without a mouse for weeks.

My first MX Master 3S had a bad right or left click button on Day 1, which would miss clicks constantly. Thankfully it was pretty easy to get a warranty replacement for this, which came as a full retail-boxed unit, so I now have an extra receiver too (I understandably had to mail in the useless defective mouse itself).

Nope, it's a known logitech problem. A couple of my Logitech mice started to get double-click issues later in their life. They cheap out with the switches, the Kailh ones don't have those issues.

It's highly variable. Some last much longer than others. The microswitches they use are very common jellybean parts and Logitech probably changes manufacturers all the time.