Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32h5/STM32H533/FDCAN/FDCAN_TXFQS#0x0
TFQF=B_0x0
FDCAN Tx FIFO/queue status register
Tx FIFO free level
Tx FIFO get index
Tx FIFO/queue put index
Tx FIFO/queue full
0 (B_0x0): Tx FIFO/queue not full
1 (B_0x1): Tx FIFO/queue full
https://github.com/modm-io/cmsis-svd-stm32