I thought a lot about the behaviour of the RFSW FM8625H when no power is applied to the VDD pin.
I came to the conclusion that the ANT is never connected to either RF port and that the signal is leaking because it is not sufficiently isolated. Therefore, when using the antenna switch, it is correct to explicitly apply power to the switch and set the selection signal to HIGH or LOW. (The ESP32C6 wiki says so)
With this in mind, the diagram shown in POST1 is modified.
