Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32u5/STM32U575/OTG_FS/DIEPTXF1#0x0
OTG device IN endpoint transmit FIFO 1 size register
INEPTXSA
INEPTXFD
https://github.com/modm-io/cmsis-svd-stm32