You clearly missed something in the former or latter or do not know how to verify if stuff is as expected. Usually I build out the DC bias model (static operat

You clearly missed something in the former or latter or do not know how to verify if stuff is as expected. Usually I build out the DC bias model (static operating point), test it in LTspice, then add the AC/small signal model on top. Or large signal model for switching etc. Everything generally works unless I did something stupid or it’s RF where things get a little less predictable.