The technical specifications of Airspy HF+ says;
+10 dBm Maximum RF input.
Since the maximum RF output power of IC-7410 is 100W, we need the attenuation of 40dB or more with an antenna switch.
A very rough experiment shows that with the TX RF output power of 35dBm at 7MHz the leak to the RX port is around -6dBm (=S9+67dB), which means the attenuation of 41dB.