STM32U5 use the core ARM M33 @160MHz (is an evolution of M4) with security improvement and low consumption.
Microvisor and STM32U5, the Best Performance-per-Watt MCU, 1st to Support a New IoT Development Paradigm, see here.
The first evaluation board will be the: B-U585I-IOT02A (Discovery kit for IoT node that combines the STM32U5 with a Wi-Fi® module, Bluetooth® module, and various sensors.)
LINK