Forget the appraiser, forget the AMC, forget FHA.
Did you or did you not have a septic tank professional;
Do a pipe, camera inspection?
Sludge and scum level measurement?
Review the service report from previous inspections?
Consult with the local building, planning department, to ensure compliance with septic tank codes?
Caveat Emptor.
If the appraiser mischecked boxes, cropped photos to hide deficiencies, and you felt was generally incompetent, report them into their local board.
As for appraisal management companies, you're not going to have a lot of argument from appraisers that they're scum of the earth. Report them too.
As for checking major "unseen" components for their soundness....that's on you.