iCloud sync

iCloud does not provide “remote access” as you appear to have possibly inferred.

It DOES help keep your devices “synchronized” data-wise …

… however each device is still accessed with a locally-entered passcode (iOS, iPadOS, WatchOS) or password (MacOS).

You might find other informative info here:

iCloud User Guide – Apple Support (AU)

From the iPhone itself you can see synced devices Check your Apple ID device list to find where you're signed in - Apple Support