The Wirecutter has a list of all of the new iOS 14 privacy alerts and what they actually mean. For instance, that one that says “XYZ App would like find and connect to devices on your local network”?
Sometimes, apps have valid reasons for accessing devices on your network, namely in order to function. If you have Sonos speakers, for example, the Spotify app won’t see them unless you allow the app to access your local network. The same goes for devices such as a Chromecast and for most smart-home-related apps. In these cases, you should approve the request.
But other apps have no justification to access this type of information. For example, my banking app asked for it, for some reason, and so does Facebook. If you can’t imagine why an app would need this permission, don’t allow it.
I don’t think I’ve allowed a single app this permission yet.