Upset Prevention and Recovery Training is mandatory for FAA Part 121 (Air Carriers) flight crew.

It is not required for Part 91 (General Aviation/"Private") or Part 135 (Charter) operators.

https://www.faa.gov/documentLibrary/media/Advisory_Circular/...

Upset and departure are different things. Some aircraft can seem strait and level, but still be fully departed and falling like a rock. This won't happen in a Cessna trainer. It is normally associated with faster aircraft. The F-16 famously has a deep stall mode that sees it fall like a pancake for many thousand feet, with little hope of recovery at low altitudes.

In the US, spin recovery training is mandatory for flight instructors. That’s the only requirement I’m aware of, although all pilots do get some relatively basic training in unusual attitude recovery.