Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/WGM160/WGM160PX22KGN3/ETH/TXBDCTRL#0x0
TX BD control register
TX Descriptor Timestamp Insertion mode, 00: TS insertion disable, 01: TS inserted for PTP Event Frames only, 10: TS inserted for All PTP Frames only, 11: TS insertion for All Frames
https://github.com/cmsis-svd/cmsis-svd-data