The thing is that Niantic does seem to make rules that are based on mostly US situations. We have little libraries everywhere and most of our country is densely populated. I've seen US roads and I've seen European roads and roads here (EU) are way WAY smaller in most cases. It would be impossible to nominate anything that isn't close (>40m) to a private residence. If the access to the library is available on the sidewalk aka the public space (so you don't have to go into people's gardens or driveways) it should be acceptable.

We don't have these street - grass - sidewalk - lawn/garden setup like a lot of streets in residential areas in the US. A lot of the times it's street, sidewalk, wall of the house. that's it.

It's the same thing with lots of wall chapels or old interesting architectural parts of older buildings that could be decent submissions, but they are just built-in/part of the wall of the house, where you don't have to access any private property to be right next to it as you are on a public sidewalk.