OK, but it looks like it's still hooked up to the rest of the circuit. If it was me I would create a different Testbench. Maybe take only a single side of the SPDT switch. Leaving out the shunt FET to start with as that's mainly for adding isolation. Then really think about what you expect those remaining components to do including the impedances seen by the inputs and outputs (and add them). And simulate to see if you get those results. Once that's working solidly you can start building upon that base.