Cosy crime is a very strange genre. It's mostly someone investigating a murder, but in a Sunday afternoon telly kind of way. An amateur detective in a small idyllic village trying to solve crimes that would be horrible in any other setting.
Think of the Miss Marple TV series. If you remember time before streaming services, when there was mostly nothing on. Obviously it's a series of Agatha Christie books as well, but we are scarred by those Sundays, so we can't say we have ever fancied picking up any copies.
If you are new to the genre, it's probably worth starting with Richard Osman's Thursday Murder Club series. That has been unbelievably popular.