At 5 Mbps the bit time is 200 ns. The transceiver propagation delay and loop delay must fit within the CAN controller's timing budget, especially when the bus length exceeds a few meters. For a 5 Mbps CAN FD network, keep the total cable length under 40 m to stay within the bit sampling window; the TCAN1042HDR's fast loop times support this without needing a slower data phase.
The 125°C ceiling means the transceiver can sit next to a hot microcontroller or power stage without derating the bus interface.