Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32u5/STM32U575/OTG_FS/DOEPTSIZ0#0x0
The application must modify this register before enabling endpoint 0.
XFRSIZ
PKTCNT
STUPCNT
https://github.com/modm-io/cmsis-svd-stm32