it’s only really us and the US that have this weird penchant for huge bowls of sweetened nursery-style milky drinks
Actually, in Russia and parts of Eastern Europe they’re very keen on Raf/Raph (раф) coffee which is certainly quite nursery-style. From Wikipedia:
‘Prepared by adding cream and vanilla sugar to a single shot of espresso and then foaming the mix with a steam heater. The main differences from latte are the use of vanilla sugar and cream instead of milk and the fact that the whole mix is foamed together instead of just milk. Syrup is often used instead of vanilla sugar.’